A research team from the Vienna University of Technology has demonstrated that due to finite energy or entropy generation, no clock can achieve both perfect resolution and precision simultaneously.
This fundamental limitation impacts the potential capabilities of quantum computers.
This discovery implies natural limits for quantum computers, as the achievable resolution and precision in timekeeping restrict the speed and reliability of quantum computations.
UNIVERSITY RESEARCH NEWS — Vienna University of Technology/November 26, 2023 — There are different ideas about how quantum computers could be built. But they all have one thing in common: you use a quantum physical system — for example, individual atoms — and change their state by exposing them to very specific forces for a specific time. However, this means that in order to be able to rely on the quantum computing operation delivering the correct result, you need a clock that is as precise as possible.
But here you run into problems: perfect time measurement is impossible. Every clock has two fundamental properties: a certain precision and a certain time resolution. The time resolution indicates how small the time intervals are that can be measured — i.e., how quickly the clock ticks. Precision tells you how much inaccuracy you have to expect with every single tick.
The research team was able to show that since no clock has an infinite amount of energy available (or generates an infinite amount of entropy), it can never have perfect resolution and perfect precision at the same time. This sets fundamental limits to the possibilities of quantum computers.
Quantum calculation steps are like rotations
In our classical world, perfect arithmetic operations are not a problem. For example, you can use an abacus in which wooden balls are threaded onto a stick and pushed back and forth. The wooden beads have clear states, each one is in a very specific place, if you don’t do anything the bead will stay exactly where it was.
And whether you move the bead quickly or slowly does not affect the result. But in quantum physics it is more complicated.
“Mathematically speaking, changing a quantum state in a quantum computer corresponds to a rotation in higher dimensions,” says Jake Xuereb from the Atomic Institute at the Vienna University of Technology in the team of Marcus Huber and first author of the first paper published in Physical Review Letters. “In order to achieve the desired state in the end, the rotation must be applied for a very specific period of time. Otherwise, you turn the state either too short or too far.”
Entropy: Time makes everything more and more messy
Marcus Huber and his team investigated in general which laws must always apply to every conceivable clock. “Time measurement always has to do with entropy,” explains Marcus Huber. In every closed physical system, entropy increases and it becomes more and more disordered. It is precisely this development that determines the direction of time: the future is where the entropy is higher, and the past is where the entropy is even lower.
As can be shown, every measurement of time is inevitably associated with an increase in entropy: a clock, for example, needs a battery, the energy of which is ultimately converted into frictional heat and audible ticking via the clock’s mechanics — a process in which a fairly ordered state occurs the battery is converted into a rather disordered state of heat radiation and sound.
On this basis, the research team was able to create a mathematical model that basically every conceivable clock must obey. “For a given increase in entropy, there is a tradeoff between time resolution and precision,” says Florian Meier, first author of the second paper, now posted to the arXiv preprint server. “That means: Either the clock works quickly or it works precisely — both are not possible at the same time.”
Limits for quantum computers
This realization now brings with it a natural limit for quantum computers: the resolution and precision that can be achieved with clocks limits the speed and reliability that can be achieved with quantum computers. “It’s not a problem at the moment,” says Huber.
“Currently, the accuracy of quantum computers is still limited by other factors, for example, the precision of the components used or electromagnetic fields. But our calculations also show that today we are not far from the regime in which the fundamental limits of time measurement play the decisive role.”
Therefore, if the technology of quantum information processing is further improved, one will inevitably have to contend with the problem of non-optimal time measurement. But who knows: Maybe this is exactly how we can learn something interesting about the quantum world.
Featured image: The oversampling regime of an exemplary clock — a pendulum in a weakly lit environment. The two sources of entropy production for this clock are: the friction within the clockwork itself, and the matter–light interaction necessary to track the position of the pendulum. The plot shows the elementary ticking events of this clock as a function of time, i.e., the photons reflected off the pendulum when it is close to its maximum deflection. In the oversampling regime, the average time between two such ticks is much shorter than that of the period of the TPC (continuous line), which in the case of this pendulum is 2 s. Due to technical limitations, one does not count photons, but rather the TPC cycles through the averaged light intensity. Credit: arXiv (2023). DOI: 10.48550/arxiv.2301.05173
BosonQ Psi’s Quantum-Inspired Design Optimization (QIDO) Solver has been validated as an effective solution for topology optimization in the aerospace and automotive industries, overcoming challenges faced by classical topology optimization methods in large-scale design problems. The study involved using the QIDO Solver to optimize airfoil structures, demonstrating its ability to efficiently handle complex design problems, such as weight minimization.
QIDO’s quantum-inspired approach, utilizing principles like superposition and entanglement, allows for simultaneous searching of larger solution spaces, resulting in better optimization than classical methods. This technology reduces the number of iterations and computing resources needed for topology optimization, offering more accurate and cost-effective solutions for airfoil structures in aircraft and automobiles.
The research highlighted the potential of QIDO Solver to dramatically improve aircraft and automobile performance and safety. Traditional topology optimization problems are typically solved using finite element analysis, but the QIDO Solver can handle complex design problems, such as minimization of the total weight of the structure, and finds global minima for obtaining optimal airfoil designs. This has implications for reducing manufacturing costs and enhancing efficiency in advanced aircraft and automobile airfoil structures.
RESEARCH NEWS— Buffalo, NY/November 15, 2023 — Design optimization finds the optimal material layout of a given structure by rearranging the material within the domain. It is classified into size, shape, and topology optimization based on the problem’s complexity. Topology optimization plays a significant role in achieving safer and more efficient designs for the aerospace and automotive industries. Different aircraft and automobile wing structures can be obtained with next-generation additive manufacturing technologies, departing from traditional rib-spar wing constructions. However, traditional topology optimization methods need to be revised when applied to aerospace structures due to their large-scale design problems.
This article will discuss the topology optimization capabilities of the Quantum-Inspired Design Optimization (QIDO) Solver, its advantages over classical methods, and the future roadmap for maximizing efficiency in advanced aircraft and automobile airfoil structures.
Figure 1: Schematic Airfoil section internal domain as design space, the outer skin as non-design space, and the wing supports are fixed.
Current Bottlenecks with the classical topology optimization techniques in Engineering Optimization:
The shape and weight of an airfoil plays a significant role in aircraft performance and safety. Topology optimization has become a priority within the aerospace and automotive industries to achieve safer and more efficient designs while reducing weight. However, computational challenges arise when dealing with high aspect-ratio wings, which require conventional density-based topology optimization methods to discretize the problem domain uniformly.
Figure 1 shows design space in blue, which is required to be discretized in the above optimization method. The complex geometry and boundary conditions turn the problem into a large-scale design optimization problem. Similarly, high aspect ratio domains of wings in aircraft or automobiles create more complex and harder-to-model design spaces [1, 2]. This limits the effectiveness of traditional classical optimization algorithms and classical computers that need an advanced solution.
Another limitation of the classical approach is that it reaches local minima instead of global minima, indicating that more efficient designs could be explored and exploited within the design process [3]. Additionally, classical optimization methods require more iterations to get optimal results for a given airfoil design, which demands more computing resources, such as GPUs and CPUs. Classical algorithms on classical computers demand more efficiency regarding the computing resources required while still delivering accuracy in topology optimization tasks.
Figure 2: The figure illustrates how, in the real world, the origin of aerodynamic forces on an airfoil section arises from the combined effects of pressure distributions and shear stress on the boundary layer.
Quantum-Inspired Approach in Design Optimization:
The Quantum-Inspired approach utilizes the principles of quantum computing, such as interference, superposition, and entanglement, to process information. By emulating these principles, the Quantum-Inspired approach allows for simultaneous searching of a larger solution space, leading to better-optimized results over classical solutions, faster convergence speed, and minimizing the usage of computing resources.
BosonQ Psi’s QIDO Solver is a Quantum-Inspired Design Optimization solver that maximizes efficiency in design engineering. QIDO’s ability to search the global optima sets it apart from traditional optimization techniques, resulting in better airfoil designs with higher performance and efficiency. The QIDO solver also significantly reduces the number of iterations required to converge to the optimal design, saving substantial simulation time. Moreover, by harnessing the power of quantum algorithms, the QIDO Solver optimizes the design using fewer computing resources, enhancing the cost-effectiveness of the design optimization process.
In the context of volume minimization of airfoil structures, the QIDO solver brings a different optimization landscape than classical methods. The low volume fraction of aerospace and automobile structures and the considerations of slenderness, buckling, and strength contribute to the complexity of optimizing low-weight, high-performance airfoil designs. By focusing on topology optimization methods, QIDO removes materials from unintended structures, meeting the demands for low-volume fraction aerospace structures, which increases the efficiency of the component.
Traditional topology optimization problems are typically solved using finite element (FE) analysis, treating each element’s presence as a design variable and aiming to find the optimal distribution of elements in the design domain [4]. This approach formulates the problem with continuous design variables, where design variables take values from 0 to 1. They produce optimal designs with fictitious elements and no clear boundary for fabricating them [4, 5].
Previous research has demonstrated that efficient topology optimization techniques can significantly enhance aircraft performance and safety. For example, Airbus’s method successfully reduced the weight of A380 components such as wingbox ribs by 10%, leading to increased stability, safety, and a 42% reduction in drag. These advancements in topology optimization have also led to cost reductions for aircraft manufacturing companies. However, for a middle-sized topology optimization problem on flexible wing structures, the number of design variables can reach up to approximately 70,000 to 100,000, making these problems incredibly complex for traditional optimization methods [2, 6].
With the QIDO (Quantum-Inspired Design Optimization) Solver from BosonQ Psi, topology optimization achieves highly optimized results for internal aircraft wing structures, improving efficiency and reducing manufacturing costs. The solver can handle complex design problems, such as minimization of the total weight of the structure, and finds global minima for obtaining optimal airfoil designs.
Figure 3: Optimal design of airfoil obtained using BQPhy’s QIDO solver
BQPhy’s topology optimization results for airfoil wings using QIDO have demonstrated remarkable outcomes. By considering the outer skin as a non-design domain, the weight of the airfoil structure can be reduced to 60% [refer to Figure 3] of its initial solid volume while maintaining its structural integrity.
Conclusion:
The QIDO presents a revolutionary approach to weight minimization in the design of airfoil structures. QIDO harnesses the principles of quantum computing and integrates them into the optimization process. This nascent methodology enables engineers to reach global minima, significantly reduces the number of iterations required, and optimizes designs using fewer computing resources. These advancements improve efficiency, reduce manufacturing costs, and the possibility of pushing the boundaries of performance and innovation in advanced aircraft and automobile airfoil structures. With QIDO, the goal of achieving safer, more efficient, and lighter designs becomes within reach for companies in the aerospace and automotive industries.
List of references:
1. Zhu, Ji-Hong, Wei-Hong Zhang, and Liang Xia. “Topology optimization in aircraft and aerospace structures design.” Archives of computational methods in engineering 23 (2016): 595–622.
2. Luis Félix, Alexandra A. Gomes2, and Afzal Suleman. “Wing Topology Optimization with Self-Weight Loading” iWorld Congress on Structural and Multidisciplinary Optimization May19, -24, 2013, Orlando,Florida, USA.
3. Stanford, Bret, and Peter Ifju. “Multi-objective topology optimization of wing skeletons for aeroelastic membrane structures.” International Journal of Micro Air Vehicles 1.1 (2009): 51–69.
4. Høghøj, Lukas C., et al. “Simultaneous shape and topology optimization of wings.” Structural and Multidisciplinary Optimization 66.5 (2023): 116.
5. Gomes, Pedro, and Rafael Palacios. “Aerodynamic-driven topology optimization of compliant airfoils.” Structural and Multidisciplinary Optimization 62 (2020): 2117–2130.
6. James, Kai. Aerostructural shape and topology optimization of aircraft wings. University of Toronto (Canada), 2012.
In a recent speech, U.S. House Representative Jay Obernolte from California discussed the transformative potential of quantum computing (QC) in both the industrial and governmental sectors. He said that QC is not merely about faster processing but also about its unique capabilities to enhance various workflows and missions, especially within federal agencies.
Obernolte’s business career in technology began with the founding of FarSight Studios, a video game development company, in 1988. He established this company while still a student, and it has since become known for developing well-regarded games for various platforms. Obernolte’s role at FarSight demonstrates his entrepreneurial spirit and expertise in the tech industry, showcasing his ability to lead and innovate in a dynamic and competitive field. His success in the video game industry provided a strong foundation for his later efforts in public service and politics and is a clear reason — it seems — why he advocates a future that includes QC.
“Quantum Computing is going to be a revolutionary game changer in many areas of industry and also in government.”
— Jay Obernolte
Obernolte emphasized the significance of an amendment that instructs the National Science Technology Council Subcommittee on Quantum Information Science to initiate an outreach program for federal agencies. This program aims to help these agencies identify practical applications of quantum computing that can significantly enhance their operations. He clarified that this amendment does not entail additional funding or expand government mandates. Instead, it focuses on guiding federal agencies to recognize and utilize quantum computing’s potential based on the council’s recommendations.
Additionally, Obernolte expressed his support for a crucial part of the bill related to the development of quantum testbeds. He noted that the amendment introduces important changes to the grant program’s eligibility criteria. It limits the number of awardees to five, ensuring a minimum of $10 million available for each, which is crucial for the program’s efficacy. The amendment also encourages applications that include substantial cost-sharing, aligning with the principles of good governance and resource optimization. Lastly, he mentioned the establishment of a one-year timeframe to set up and operate the grant program, emphasizing efficiency and prompt implementation.
“[…] quantum computers are much more than just computers that run faster than traditional computers and it’s often not obvious to industry or particularly to federal agencies how quantum computing can be integrated into their workflows, and how it can be used to improve their missions. So, that’s why this amendment is so important. It requires the National Science Technology Council Subcommittee on Quantum Information Science to establish a programme of outreach to federal agencies to help them identify the use cases that quantum can help to solve meaningfully.”
The Chicago Quantum Exchange (CQE), through its Open Quantum Initiative (OQI) Fellowship Program, in collaboration with the Argonne National Laboratory, recently facilitated a unique opportunity for undergraduate students. This summer, eight out of 18 OQI fellows participated in the program, contributing significantly to the Q-NEXT research and development, a project under the U.S. Department of Energy’s National Quantum Information Science Research Center led by Argonne.
These fellows, immersed in quantum science laboratories and research groups, experienced first-hand the dynamic world of quantum information science and engineering (QISE). For many, it was their inaugural foray into the realm of QISE, offering them a comprehensive understanding of the life and responsibilities of a scientist in a laboratory setting. They learned to actively participate in research groups and effectively communicate complex experimental results.
A highlight of the program was a visit to HRL Laboratories in California, coupled with a symposium where the fellows presented their research findings.
In a recent Q&A, these eight fellows shared their experiences and insights gained from investigating various aspects of quantum information science and engineering during their summer with the Q-NEXT program. This fellowship has been a crucial step in driving the advancement of technology using the properties of nature’s smallest particles.
Atlas Sébastien Bailly
Atlas Sébastien Bailly.
Home institution: Cornell University Major: Physics, mathematics OQI institution: Argonne National Laboratory Faculty mentor: Paul Kairys, postdoctoral appointee
Q: What was the focus of your OQI research this summer?
A: Autonomous characterization of nitrogen-vacancy centers in diamond. Initially, I worked on a computer model of the nitrogen-vacancy center, then used the model to explore optimal Bayesian experimentation.
Q: What was your role?
A: I was given a lot of freedom to explore my own ideas while working with my mentor on an existing project.
Q: What have you gained from the OQI experience?
A: By working with scientists and constantly being engaged with researchers or new startups through the OQI, I gained a lot of soft knowledge about QISE and science at large. Through my work, I built many practical skills and a foundational image of how science is done.
Q: What new perspectives do you have about QISE?
A: “Quantum stuff” has taken on an almost mythical/sci-fi aura in the public eye. This summer I learned that QISE is not composed of a top-secret Google basement but of a wide range of people with different technical goals and interests.
Q: What’s next for you?
A: I greatly enjoyed my work in QISE but feel that it would be premature to commit myself to any field. I want to explore more science and math and discover what else people are working on.
Q: What do you enjoy doing outside of research?
A: I’m an avid rock climber and outdoorsman, I love reading of all sorts, and in the past year I’ve rediscovered my passion for football (soccer).
Q: What advice do you have for other young people who are interested in pursuing a career in QISE?
A: Explore your interests before anything! The world is broad and QISE itself is unimaginably diverse.
Anais El Akkad
Anais El Akkad.
Home institution: Georgia Institute of Technology Major: Physics OQI institution: University of Illinois Urbana-Champaign Faculty mentor: Elizabeth Goldschmidt, assistant professor of atomic, molecular and optical physics
Q: What was the focus of your OQI research this summer?
A: My OQI research this summer focused on studying the phenomenon of superradiance in a rare-earth doped crystal, which has potential applications to the development of quantum memories.
Q: What was your role?
A: I mainly worked on the experimental set-up, gaining lots of hands-on experience with arranging and aligning optics, as well as learning how to operate the laser.
Q: What have you gained from the OQI experience?
A: So much! I think I learned more this past summer than I have in any class. Being able to do hands-on work and see how science is done has truly reaffirmed my passion for physics. I also think the community is phenomenal — everybody involved in OQI, including my labmates, my peer OQI fellows and everybody who worked tirelessly to ensure we had a good experience were incredibly supportive and friendly and really made me feel like I belong in QISE.
Q: What new perspectives do you have about QISE?
A: I’ve learned how diverse and interdisciplinary QISE is. There are so many people from all sorts of different backgrounds working on various problems in quantum information. It’s such a vast field — there are so many ways to be involved in quantum.
Q: What’s next for you?
A: After my undergrad, I hope to pursue graduate studies and further immerse myself in the exciting research within QISE.
Q: What do you enjoy doing outside of research?
A: I love reading, hiking, baking and playing piano.
Q: What advice do you have for other young people who are interested in pursuing a career in QISE?
A: Don’t be afraid to seek new opportunities! Even if you don’t feel qualified, take every chance you get to meet professionals in the field, gain some hands-on experience and just put yourself out there. I never would have expected to find myself working in a quantum optics lab, and I’m so grateful to the OQI program for this amazing opportunity.
Gabriel Gaeta
Gabriel Gaeta.
Home institution: San Jose State University Major: Physics OQI institution: Argonne National Laboratory Faculty mentor: Jiefei Zhang, applied physicist, assistant staff scientist
Q: What was the focus of your OQI research this summer?
A: My research was focused on the growth of single-crystal thin films doped with rare-earth spin qubits and characterizing those qubits in the crystals through optical measurements in order to find optimal coherence times for quantum memory applications. I was primarily focused on growing erbium in cerium dioxide that would be used as a memory qubit for a quantum network.
Q: What was your role?
A: My role was that of a student researcher — I was given a lot of freedom within the constraints of working within a group, and I was also offered the guidance needed to achieve my goals. My work consisted of material growth in which I formed thin-layer depositions of single-crystal cerium dioxide on a substrate surface. I also gathered data through optical measurements by shooting a laser at the grown film and looked at emission as a way of characterizing the quality of grown film.
Q: What have you gained from the OQI experience?
A: I have gained numerous skills from simply working in the lab through this summer. But something I gained that was invaluable was experiencing the dynamic of working in a research group. It gave me insight into what goes on behind the research as well as into the different types of roles you can have as a researcher.
Q: What new perspectives do you have about QISE?
A: It’s a field of science that is still young and has immense potential and implications in the future. Quantum computers, quantum sensing and quantum communication were all things that I had no idea were possible prior to my opportunity with OQI and the CQE.
Q: What’s next for you?
A: Continuing my undergraduate program at San Jose State and pursuing other research opportunities in the future. I always want to have a plan as to what I will do once I am done with my main goal, and after my bachelor’s degree, I would love to pursue graduate school.
Q: What do you enjoy doing outside of research?
A: I am an avid film and TV lover. I love being immersed in entire other worlds and storylines, especially films that simply explore the human experience and the difficulties that go along with that. My favorite genres consist of dramas, science fiction, thrillers and biopics.
Q: What advice do you have for other young people who are interested in pursuing a career in QISE?
A: Have an open mind and go for it! I love being receptive to new ideas, and quantum was one of those. I had no idea that I was going to enjoy quantum research as much as I did, but I tried it and got to experience a wonderful time with so many like-minded people. Don’t let your doubts hold you back!
Kenneth Muhammad
Kenneth Muhammad.
Home institution: Massachusetts Institute of Technology Major: Electrical science and engineering OQI institution: University of Illinois Urbana-Champaign Faculty mentor: Paul Kwiat, Sony Bardeen chair in physics and electrical and computer engineering
Q: What was the focus of your OQI research this summer?
A: Our goal was to implement an active stabilization scheme for a tabletop interferometer setup and photonic integrated chip setup for use in time-bin encoding of quantum information.
Q: What was your role?
A: I built a tabletop Michelson interferometer setup and programmed a microcontroller to actively control the position of a translation stage using a piezoelectric actuator. I wrote some accompanying code to easily modify the control parameters and calculate the optimal set point using Python. I spent time learning theory as well and used this knowledge to inform my design.
Q: What have you gained from the OQI experience?
A: I have gained practical experience building optical setups, programming microcontrollers and designing a system that is user-friendly. Perhaps the most useful experience I have received is working with other researchers in the lab and both communicating my ideas clearly and asking them the right questions so as to learn as much as possible. Working in the lab allowed me the unique opportunity to learn things like quantum information science alongside building a project that uses the same theory, and I don’t think I could have gotten that anywhere else.
Q: What new perspectives do you have about QISE?
A: I used to not think much of the quantum technologies of today due to their lack of tangible applications and my lack of knowledge on the subject. Now, I believe that QISE is a rapidly growing field and there are likely many applications that we haven’t thought of yet. I’m excited to see what new branches of technology emerge as this whole thing unfolds.
Q: What’s next for you?
A: I am interested in learning more about applications of quantum information science, so I will likely find myself working in a lab continuing research in something that combines electronics and quantum mechanics. I’m also hoping to use my math background to dive deeper into the potential of this field.
Q: What do you enjoy doing outside of research?
A: I mainly enjoy playing video games, reading books and going for walks in places I’ve never been.
Q: What advice do you have for other young people who are interested in pursuing a career in QISE?
A: Pursue what you enjoy and play to your strengths.
Natasha Ninan
Natasha Ninan.
Home institution: University of Akron Major: Electrical engineering OQI institution: University of Wisconsin–Madison Faculty mentor: Mikhail Kats, associate professor of electrical and computer engineering
Q: What was the focus of your OQI research this summer?
A: Our group is working on the design and fabrication of an optical bottle beam trap using a metasurface. Optical bottle beam traps are used to create optical tweezers for quantum devices such as atomic clocks or quantum computers. I worked on designing of the metasurface structure using the finite difference time domain (FDTD) method, which models the electrodynamics using Maxwell’s equations. Other group members are working on fabricating the resulting devices.
Q: What was your role?
A: The challenges in using scanning electron microscope imaging to assess the fabricated structure performance to the design necessitated the development of a simpler method to evaluate overall metasurface performance. I designed the witness sample metasurface that will be fabricated to easily evaluate the fabrication quality.
Q: What have you gained from the OQI experience?
A: Working in the Kats Research Group enabled me to learn more about optical trapping of atoms. In addition, I was able to learn how to design metasurfaces using FDTD and simulate possible fabrication error scenarios.
Q: What new perspectives do you have about QISE?
A: Being a part of Kats Research Group and the US Quantum Information Science School this summer has given me insight into different qubit creation methods. The various methods such as superconducting, trapped ions and photonic qubits present unique advantages. While these approaches have room for improvement, I expect the various qubit creation methods to become more application-specific.
Q: What’s next for you?
A: As a rising senior, I am working on applying for graduate school. This internship has given me the opportunity to explore my research interests. As I navigate the application process, I will be actively seeking projects in the fields of optical engineering, photonics and quantum sensing.
Q: What do you enjoy doing outside of research?
A: Traveling and hiking. When I’m not working on my coursework and research, I’m usually diving into researching new travel destinations and hiking adventures.
Q: What advice do you have for other young people who are interested in pursuing a career in QISE?
A: QISE is a multidisciplinary field. Having multiple opportunities in academia, industry and the national labs is very important to understand where you would like to contribute in QISE. In addition, it is equally as important to network and be open to hearing about the career paths of researchers in the field. This can provide valuable insights into your own path.
Peter Mugaba Noertoft
Peter Mugaba Noertoft.
Home institution: Stanford University Major: Electrical engineering OQI institution: University of Chicago Faculty mentor: David Awschalom, Liew Family professor of molecular engineering, UChicago; senior scientist, Argonne; director of the Chicago Quantum Exchange
Q: What was the focus of your OQI research this summer?
A: This summer I joined the quantum sensing efforts in the Awschalom group working on magnetometry with the nitrogen-vacancy center in diamond.
Q: What was your role?
A: My role was to establish scanning probe magnetic field sensing capabilities to be used for characterization of various quantum devices. The goal is to use information about distributions of magnetic fields to learn about relevant device physics. This involved building an optical setup for confocal microscopy and creating instrument control code to network the necessary lab equipment.
Q: What have you gained from the OQI experience?
A: Through the OQI experience, I’m excited to have gained a deeper insight into what it means to be a scientist working in a lab. I’ve also enjoyed getting to know all the other fellows, who share a strong interest in quantum science and engineering.
Q: What new perspectives do you have about QISE?
A: This summer I’ve learned about the sheer breadth of opportunities related to quantum science and engineering. It has been very inspiring to hear how the problems people choose to work on are often related to their unique backgrounds and interests.
Q: What’s next for you?
A: I’ve really enjoyed spending my summer in a research lab, gaining hands-on experience as a scientist and engineer. During the upcoming academic year, I’m excited to continue working on my research project at my home institution and thinking about what role I can play in the world of science long term.
Q: What do you enjoy doing outside of research?
A: I am an avid cyclist and love outdoor bike rides. I also enjoy playing recreational soccer and basketball.
Q: What advice do you have for other young people who are interested in pursuing a career in QISE?
A: I would encourage anyone with an interest in quantum science and engineering to consider a wide range of ways to get involved. Doing is an excellent way of learning!
Rachelle Rosiles
Rachelle Rosiles.
Home Institution: Illinois Institute of Technology Major: Physics OQI Institution: Argonne National Laboratory Faculty Mentor: Nazar Delegan, assistant scientist
Q: What was the focus of your OQI research this summer?
A: The group I worked with this summer conducted experiments on the growth and characterization of nitrogen-vacancy centers in diamonds for quantum sensing on the diamond surface. I was particularly involved in the process of optically addressing and manipulating the qubit.
Q: What was your role?
A: For my role, I adapted the control software, nspyre, to integrate new optical devices and create more self-driven experiments.
Q: What have you gained from the OQI experience?
A: I gained perspective on different opportunities in quantum science in both industry and academia. The connections I made have been extremely rewarding by exposing me to new fields and opening up opportunities for me.
Q: What new perspectives do you have about QISE?
A: I see now that industry and academia are not mutually exclusive. Plenty of startups have spawned from research groups and have backgrounds in academia, while industries in quantum science rely heavily on people who can conduct research on the product they’re developing. I’ve also come to realize that there is a lot of investment and momentum in this field, so I know it is a great time to be getting in.
Q: What’s next for you?
A: I’m looking to continue my work in research as I figure out if graduate school is the path for me. There are some researchers I’m interested in working with next summer in quantum computing.
Q: What do you enjoy doing outside of research?
A: I enjoy caring for my plants, watching them grow and shaping the bonsai I have.
Q: What advice do you have for other young people who are interested in pursuing a career in QISE?
A: I would say that now is the perfect time to do so, whether your interest lies in the science, organization or the business side. There’s plenty of work to do, and many people are willing to talk and advise on how to get into the field, whether through the OQI fellowship or other means. Don’t let the word “quantum” intimidate because it is really not that inaccessible.
Rain Wang
Rain Wang.
Home institution: Harvard University Major: Physics OQI institution: Argonne National Laboratory Faculty mentor: F. Joseph Heremans, staff scientist, Argonne; affiliated scientist at the Pritzker School of Molecular Engineering at the University of Chicago
Q: What was the focus of your OQI research this summer?
A: Both projects that I worked on aimed toward realizing real-world quantum networking. In quantum networking, like any network, you have nodes, and you have connections that are essential to the network’s function. This summer, my main project optimized the connections in the Chicago Quantum Network, while my second project delved into characterizing a potential node for quantum communication.
Q: What was your role?
A: For my main project, I performed various analysis techniques to characterize the polarization drift in the fibers and eventually implement a protocol that would correct this drift (later phase as well). This was important for retaining information and clear communication. In my second project, I designed, optimized and built an optical/modulator setup that would enable the characterization of vanadium spin-defects in silicon carbide so that we can further understand its properties and potential for quantum communication.
Q: What have you gained from the OQI experience?
A: I am extremely grateful for the wealth of knowledge, relationships and resources that I have gained from the OQI experience. I had never been able to explore quantum this deeply prior to OQI, and this time has invigorated my curiosity and motivation to pursue such a new and exciting field through different avenues.
Q: What new perspectives do you have about QISE?
A: There is so much more opportunity in this field than I think I previously understood. There are research, entrepreneurial and communications opportunities — and more. Further, while current industry eyes are mostly on quantum computing, this experience has led to my developing interest in quantum sensing and communication. I’m excited to explore.
Q: What’s next for you?
A: I’m curious to explore the different sides of quantum beyond research. Quantum is such an interdisciplinary field — I want to see all its potential. While I love science, I am curious about industry-side roles and how to facilitate this science becoming accessible to the public. In summary: I’m not sure, but I am looking forward to finding out!
Q: What do you enjoy doing outside of research?
A: On campus, I am involved in activities from our Asian American Dance Troupe to Tech for Social Good club. I am very passionate about accessible education and empowering underrepresented people in STEM. I involve myself in mentorship programs and affinity groups that realize those goals. I also love to cook, bake, exercise and paint with friends and family.
Q: What advice do you have for other young people who are interested in pursuing a career in QISE?
A: It’s never too early to discover your passions! There are so many available opportunities and resources to start investigating quantum at any age, you just have to look (OQI is an amazing example). It can be extremely daunting, but you can take that first step. Don’t be afraid to reach out to people; people are always happy to help.
The experience of participating in the Open Quantum Initiative (OQI) Fellowship Program reaffirmed the above students’ passion for physics and science, broadening their perspectives and opening up new academic and career possibilities in QISE. Many expressed a desire to continue exploring this field through further studies and research, demonstrating the program’s success in inspiring the next generation of quantum scientists and engineers.
Funding was provided by the University of Chicago, The U.S. Department of Energy Office of Technology Transitions and Q-NEXT, the Illinois Quantum Information Science and Technology Center at the University of Illinois Urbana-Champaign, HQAN at the University of Wisconsin–Madison, the Ohio State University, Gordon and Betty Moore Foundation, and UChicago’s Inclusive Innovation in the Sciences Fund.
A universal quantum computer, capable of executing any quantum operation, has vast potential applications in the real world, extending beyond specific uses like solving optimization problems.
In 2022, Fellner and Messinger — along with physicists Kilian Ender and Wolfgang Lechner — unveiled a new universal gate set for quantum computers. This development, rooted in the ParityQC Architecture, boasts all-to-all connectivity and inherent error correction capabilities. Their research, titled “Universal Parity Quantum Computing,” was published in the journal Physical Review Letters.
In the short video, Fellner and Messinger describe how the essence of their work revolves around the Parity Code, which doubles as a stabilizer code defined by specific parity constraints. They explain how the product of the eigenvalues of two qubits correlates with the eigenvalue of a third qubit, illustrating a fundamental aspect of their approach. This relationship is central to their definition of ‘parity qubits,’ where one qubit represents the parity of others.
In terms of quantum operations, their methodology facilitates the implementation of certain multi-qubit interactions. For example, they can easily execute operations like the RS ad set gate through simple local operations on parity qubits. However, they acknowledge the complexity of implementing other interactions within this framework.
To address these challenges, they’ve devised a strategy that combines direct single qubit interactions with more complex ones enabled by the Parity encoding. This innovative approach involves alternating between blocks of gates within the Parity encoding and others applied directly to the qubits. Remarkably, they’ve developed a method that allows this interchange with only a constant time overhead, leveraging measurements and classical information processing akin to quantum teleportation.
Their approach is reminiscent of quantum repeaters, where a sequence of local entangling gates and measurements can generate long-range entanglement. They’ve applied this method to execute the quantum approximate optimization algorithm (QAOA) in constant time, independent of system size, a significant step towards realizing quantum advantage with imminent quantum devices.
This development by Keller, Messinger, and the team at ParityQC represents a pivotal advancement in quantum computing. The potential of this technology is immense, and its future applications are eagerly anticipated.
Researchers at Texas A&M University utilized quantum computing to map gene regulatory networks (GRNs), revealing new gene relationships previously undetectable with traditional computing methods, which could significantly impact both animal and human medicine.
Quantum computing allowed for more complex analysis of gene interactions, overcoming limitations of older technologies that could only compare two genes at a time, thus providing a more complete picture of how genes influence each other.
The study, part of a new and rapidly developing field, involved both biomedical scientists and engineers, and future plans include comparing healthy cells with those affected by diseases or mutations to understand the impact of these changes on gene states and expressions.
UNIVERSITY RESEARCH NEWS — Colleg Station, Texas/November 20, 2023 — In a new multidisciplinary study, researchers at Texas A&M University showed how quantum computing — a new kind of computing that can process additional types of data — can assist with genetic research and used it to discover new links between genes that scientists were previously unable to detect.
Their project used the new computing technology to map gene regulatory networks (GRNs), which provide information about how genes can cause each other to activate or deactivate.
As the team published in npj Quantum Information, quantum computing will help scientists more accurately predict relationships between genes, which could have huge implications for both animal and human medicine.
“The GRN is like a map that tells us how genes affect each other,” Cai said. “For example, if one gene switches on or off, then it may change another gene that could change three, or five, or 20 more genes down the line.
“Because our quantum computing GRNs are constructed in ways that allow us to capture more complex relationships between genes than traditional computing, we found some links between genes that people hadn’t known about previously,” he said. “Some researchers who specialize in the type of cells we studied read our paper and realized that our predictions using quantum computing fit their expectations better than the traditional model.”
The ability to know which genes will affect other genes is crucial for scientists looking for ways to stop harmful cellular processes or promote helpful ones.
“If you can predict gene expression through the GRN and understand how those changes translate to the state of the cells, you might be able to control certain outcomes,” Cai said. “For example, changing how one gene is expressed could end up inhibiting the growth of cancer cells.”
Members of the Cai Lab (l-r): master’s student Victoria Gatlin, doctoral student Shreyan Gupta, doctoral student Cristhian Roman Vicharra, postdoctoral researcher Dr. Selim Romero Gonzalez, Dr. James Cai, doctoral student Qian Xu, and master’s student Amy Barrett.
Texas A&M University School of Veterinary Medicine and Biomedical Sciences
Making The Most Of A New Technology
With quantum computing, Cai and his team are overcoming the limitations of older computing technologies used to map GRNs.
“Prior to using quantum computing, the algorithms could only handle comparing two genes at a time,” Cai said.
Cai explained that only comparing genes in pairs could result in misleading conclusions, since genes may operate in more complex relationships. For example, if gene A activates and so does gene B, it doesn’t always mean that gene A is responsible for gene B’s change. In fact, it could be gene C changing both genes.
“With traditional computing, data is processed in bits, which only have two states — on and off, or 1 and 0,” Cai said. “But with quantum computing, you can have a state called the superposition that’s both on and off simultaneously. That gives us a new kind of bit — the quantum bit, or qubit.
“Because of superposition, I can simulate both the active and inactive states for a gene in the GRN, as well as this single gene’s impact on other genes,” he said. “You end up with a more complete picture of how genes influence each other.”
Taking The Next Step
While Cai and his team have worked hard to show that quantum computing is helpful to the biomedical field, there’s still a lot of work to be done.
“It’s a very new field,” Cai said. “Most people working in quantum computing have a physics background. And people on the biology side don’t usually understand how quantum computing works. You really have to be able to understand both sides.”
That’s why the research team includes both biomedical scientists and engineers like Cai’s Ph.D. student Cristhian Roman Vicharra, who is a key member of the research team and spearheaded the study behind the recent publication.
“In the future, we plan to compare the healthy cells to ones with diseases or mutations,” Cai said. “We hope to see how a mutation might affect genes’ states, expression, frequencies, etc.”
For now, it’s important to get as clear an understanding as possible of how healthy cells work before comparing them to mutated or diseased cells.
“The first step was to predict this baseline model and see whether the network we mapped made sense,” Cai said. “Now, we can keep going from there.”
Written by Courtney Price, Texas A&M University School of Veterinary Medicine and Biomedical Sciences
Featured image: (l-r) Professor James Cai and Ph.D. student Cristhian Roman Vicharra. Credit: Texas A&M University School of Veterinary Medicine and Biomedical Sciences
A team led by researchers from the Quantum Science Center at Oak Ridge National Laboratory confirmed the presence of quantum spin liquid (QSL) behaviour in the material KYbSe2, aligning with physicist Phil Anderson’s 1973 hypothesis about QSL states in triangular lattices.
QSLs are an unusual state of matter in which magnetic atoms called spins are entangled, and they exhibit properties useful in developing superconductors and quantum computing components. KYbSe2, a delafossite, has layered triangular lattices ideal for studying QSL behaviour.
The research team used advanced techniques to identify QSL features in KYbSe2 and found the material was close to the quantum critical point where QSL characteristics thrive. The study, a significant step in understanding QSLs, may lead to advances in next-generation quantum technologies.
RESEARCH NEWS — Oak Ridge National Laboratory/November 16, 2023 — In 1973, physicist Phil Anderson hypothesized that the quantum spin liquid, or QSL, state existed on some triangular lattices, but he lacked the tools to delve deeper. Fifty years later, a team led by researchers associated with the Quantum Science Center headquartered at the Department of Energy’s Oak Ridge National Laboratory has confirmed the presence of QSL behavior in a new material with this structure, KYbSe2.
QSLs — an unusual state of matter controlled by interactions among entangled, or intrinsically linked, magnetic atoms called spins — excel at stabilizing quantum mechanical activity in KYbSe2 and other delafossites. These materials are prized for their layered triangular lattices and promising properties that could contribute to the construction of high-quality superconductors and quantum computing components.
The paper, published in Nature Physics, features researchers from ORNL; Lawrence Berkeley National Laboratory; Los Alamos National Laboratory; SLAC National Accelerator Laboratory; the University of Tennessee, Knoxville; the University of Missouri; the University of Minnesota; Stanford University; and the Rosario Physics Institute.
“Researchers have studied the triangular lattice of various materials in search of QSL behavior,” said QSC member and lead author Allen Scheie, a staff scientist at Los Alamos. “One advantage of this one is that we can swap out atoms easily to modify the material’s properties without altering its structure, and this makes it pretty ideal from a scientific perspective.”
Using a combination of theoretical, experimental and computational techniques, the team observed multiple hallmarks of QSLs: quantum entanglement, exotic quasiparticles and the right balance of exchange interactions, which control how a spin influences its neighbors. Although efforts to identify these features have historically been hindered by the limitations of physical experiments, modern neutron scattering instruments can produce accurate measurements of complex materials at the atomic level.
By examining KYbSe2’s spin dynamics with the Cold Neutron Chopper Spectrometer at ORNL’s Spallation Neutron Source — a DOE Office of Science user facility — and comparing the results to trusted theoretical models, the researchers found evidence that the material was close to the quantum critical point at which QSL characteristics thrive. They then analyzed its single-ion magnetic state with SNS’s Wide-Angular-Range Chopper Spectrometer.
The witnesses in question are the one-tangle, two-tangle and quantum Fisher information, which has played a key role in previous QSC research focused on examining a 1D spin chain, or a single line of spins within a material. KYbSe2 is a 2D system, a quality that made these endeavors more complex.
“We are taking a co-design approach, which is hardwired into the QSC,” said Alan Tennant, a professor of physics and materials science and engineering at UTK who leads a quantum magnets project for the QSC. “Theorists within the center are calculating things they haven’t been able to calculate before, and this overlap between theory and experiment enabled this breakthrough in QSL research.”
This study aligns with the QSC’s priorities, which include connecting fundamental research to quantum electronics, quantum magnets and other current and future quantum devices.
“Gaining a better understanding of QSLs is really significant for the development of next-generation technologies,” Tennant said. “This field is still in the fundamental research state, but we can now identify which materials we can modify to potentially make small-scale devices from scratch.”
Although KYbSe2 is not a true QSL, the fact that about 85% of the magnetism fluctuates at low temperature means that it has the potential to become one. The researchers anticipate that slight alternations to its structure or exposure to external pressure could potentially help it reach 100%.
QSC experimentalists and computational scientists are planning parallel studies and simulations focused on delafossite materials, but the researchers’ findings established an unprecedented protocol that can also be applied to study other systems. By streamlining evidence-based evaluations of QSL candidates, they aim to accelerate the search for genuine QSLs.
“The important thing about this material is that we’ve found a way to orient ourselves on the map so to speak and show what we’ve gotten right,” Scheie said. “We’re pretty sure there’s a full QSL somewhere within this chemical space, and now we know how to find it.”
Featured image: An illustration of the lattice examined by Phil Anderson in the early ’70s. Shown as green ellipses, pairs of quantum particles fluctuated among multiple combinations to produce a spin liquid state. Credit: Allen Scheie/Los Alamos National Laboratory, U.S. Dept. of Energy
In the realm of laser-powered quantum computers, a critical need exists for a system capable of precisely counting and differentiating individual light particles, known as photons. For such quantum computers to function effectively, they require the capability to discern over 50 photons in mere nanoseconds.
A team of experts in a collaborative effort from the Thomas Jefferson National Accelerator Facility and the University of Virginia has now developed, constructed, and successfully tested a photon detection system tailored for this purpose, achieving a remarkable feat by accurately resolving over 100 photons in just a few microseconds. This breakthrough not only demonstrates the practicality of laser-powered quantum computers but also paves the way for the integration of a “cubic phase gate,” which is crucial for enhancing the robustness and fault tolerance of quantum computing calculations.
This advancement in photon detection technology marks a significant leap in quantum computing capabilities. It holds immense potential not only in scientific advancements but also in elevating economic development and bolstering national security. Traditional computer-generated random numbers, though seemingly arbitrary, are derived from algorithms that are potentially vulnerable to decryption. The quantum generation of genuinely random numbers, facilitated by this new technology, promises the creation of indecipherable codes and encryptions, which are vital in military and financial applications.
The quest for quantum computing has led researchers to explore photonic systems, which entirely rely on light. Accurate quantum detection of photons is a cornerstone of such systems. Existing prototype detectors in this domain can typically identify less than 20 photons. However, simulations indicate that effective quantum computing demands the detection of at least 50 photons. Achieving this threshold is synonymous with the successful implementation of a “cubic phase gate,” a critical component in establishing a comprehensive gate set for universal quantum computing.
The researchers focused on an existing photon-based quantum computer setup that utilizes a pulsed laser for quantum calculations. The original photon detector in this setup fell short in rapidly and precisely counting photons before signal degradation. To address this, the team introduced a new detector system comprising three interconnected superconducting transition-edge sensor (TES) devices, complemented by a novel, high-speed digitizer. In tests, this innovative three-detector prototype not only reached the 100-photon mark but also demonstrated 12-bit accuracy.
The development and testing of this photon detection system were made possible through support from various institutions. Funding was provided by the U.S. Department of Energy Office of Science, the Office of Nuclear Physics, the National Science Foundation, the National Research Council Research Associate Program, the Air Force Research Laboratory Summer Faculty Fellowship Program, the Air Force Office of Scientific Research, and the Thomas Jefferson National Accelerator Facility Lab Directed Research and Development program.
Researchers at the University of Nebraska, in collaboration with Wichita State University, are working to improve quantum computing efficiency by seeking materials to reduce disruptions known as decoherence in quantum systems.
Funded by an $800,000 NSF award, the team aims to develop quantum materials that maintain coherence at higher temperatures, reducing the need for costly ultra-cold environments typically required for quantum computing.
The project focuses on exploring new materials like ultrathin magnetic films and two-dimensional magnetic materials to create more stable hybrid systems for quantum computers, potentially making the technology more accessible and affordable for broader applications.
UNIVERSITY RESEARCH NEWS — Lincoln, Nebraska/November 6, 2023 — By looking to create quieter environments, a team that includes Nebraska Engineering researcher Abdelghani Laraoui hopes to take a bit of the “noise” out of quantum computing and help make the emerging technology more efficient, accessible and feasible.
The goal is to find materials that show potential for improving the performance of quantum computers and that can be utilized to control the disruptions — also known as decoherence (or noise) — that keep these superfast computers from performing at their best.
“Quantum computers can do calculations in two minutes that would take 10,000 years if you used a classical system, but right now, they are difficult to scale up (for wider use) because they have to exist in very low-temperature environments, and that is very expensive to create,” said Laraoui, assistant professor of mechanical and materials engineering.
This track pairs researchers, such as Laraoui, who have extensive QISE experience with individual researchers, such as Ambal and Wang, from institutions that have less expertise in advanced nanofabrication of quantum materials and cryogenic quantum sensing.
Unlike classic computing systems, quantum computers have no memory or processors, but instead use superconductive subatomic qubits, which store and process information and are ideal for higher-level tasks — such as running simulations and analyzing data — with superfast speed and precision.
But, Laraoui said, quantum computers often need an extremely cold environment around 10 mK (equivalent to -459 Fahrenheit) to perform well with lower error rates.
“The technology for cooling is difficult to find and is very expensive,” Laraoui said. “There’s only a few places that can do it.”
To overcome the need for a super cold environment, Laraoui said the research team is looking for new quantum materials where the quantum coherence is preserved even at higher temperatures (above 2 degrees Kelvin, roughly -456 Fahrenheit).
The Nebraska Center for Materials and Nanoscience, with funding help from another NSF grant on which Laraoui was a co-investigator, will soon receive a cryogenic scanning probe microscope with quantum sensing capabilities that can operate at temperature down to 1.8 K (roughly -456.4 Fahrenheit).
In Laraoui’s Quantum Sensing and Defect Discovery and Spectroscopy Lab, mechanical engineering graduate student Rupak Timalsina and first-year electrical engineering student Ben Hammons built another cryogenic optical microscope through which researchers can witness how the qubits in diamond substrates perform under the presence of other materials in contact. Funding for this, in part, included support from NSF Emergent Quantum Materials and Technologies Center the university has received, where Laraoui serves as a thrust 2 leader on quantum technologies.
Adding qubits would increase the capacity of a quantum computer, Laraoui said, much like how classic computers can perform more complex tasks when more bits added.
However, Laraoui said, the challenge in creating a larger network of qubits is that quantum systems are fragile and “the slightest amount of decoherence can keep them from performing well.” It’s similar to how a soap bubble pops when it touches another object, loses its unique characteristics and returns to a drop of liquid.
Laraoui’s team is seeking more robust materials such as ultrathin magnetic films and two-dimensional magnetic materials and will try to use them to control spin qubits in diamond at longer distances that can work at higher temperatures.
“The idea is that we can use them to make a hybrid system that contains these spin qubits with elements of a classical system,” Laraoui said. “With hybrid architectures, like a diamond substrate, you couple them with spin waves (magnons) that have certain excitations specific to certain materials.
“The longer coherence time will lead to operating quantum computers in less challenging environments, and that could be a breakthrough that can make them less expensive and more available for wider uses.”
Featured image: Ben Hammons, a freshman in electrical engineering, and Abdelghani Laraoui, assistant professor in mechanical and materials engineering, work on laser equipment. Credit: University of Nebraska
Researchers at the University of Duisburg-Essen have developed a method for extracting data from noisy signals, a discovery that holds significant potential for quantum computing, as detailed in the latest issue of Physical Review Research.
The research focuses on quantum dots, nanometer-sized structures whose electrons can assume two different spin directions, thus functioning as qubits essential for quantum computers and the method allows for the specific preparation and measurement of the lifespan of these spin states in qubits, ensuring the stability and integrity of information.
The technique, which involves analyzing long-term noise data generated by a constantly excited quantum dot sample, can decipher the lifetime of spin states from seemingly random optical signals and aligns with Rolf Landauer’s 1998 theory that “The noise is the signal,” and it may enable reevaluation and discovery of signals in older data previously deemed unusable.
UNIVERSITY RESEARCH NEWS — University of Duisburg-Essen/November 8, 2023 — A method developed at the University of Duisburg-Essen makes it possible to read data from noisy signals. Theoretical physicists and their experimental colleagues have published their findings in the current issue of Physical Review Research. The method they describe could also be significant for quantum computers.
You know it from the car radio: The weaker the signal, the more disturbing the noise. This is even more true for laboratory measurements. Researchers from the Collaborative Research Center 1242 and the Center for Nanointegration (CENIDE) at the University of Duisburg-Essen (UDE) have now described a method for extracting data from noise.
What is a bit in a conventional computer, i.e., state 1 (current on) or state 0 (current off), is taken over in the quantum computer by the quantum bits, or qubits for short. To do this, they need defined and distinguishable states, but they can overlap at the same time and therefore enable many times the computing power of a current computer. This means they could also be used where today’s supercomputers are overtaxed, for example in searching extremely large databases.
In Collaborative Research Center 1242, the smallest structures and their changes are studied, including quantum dots. These nanometer-sized structures can be tailored in their electronic and optical properties in the laboratory. Put simply, their electrons can assume two different directions of rotation (“spin up” and “spin down”). This is how the qubits needed for quantum computers can be realized. These should be stable for as long as possible so that no information is lost.
“With our novel technique, we were able to demonstrate that spin states can be specifically prepared and at the same time determine how long such a state is maintained,” explains Dr. Eric Kleinherbers, until recently a postdoc in the Theoretical Physics group headed by Prof. Dr. Jürgen König, now at the University of California, Los Angeles.
For this purpose, a quantum dot sample was permanently exposed to an exciting laser and the resulting noise was recorded over a long period of time. The theoretical physicists led by Kleinherbers succeeded in extracting the lifetime of the spin states from this apparently random optical signal.
Rolf Landauer, a pioneer of information theory, had already predicted this finding in 1998 and summarized it with the phrase “The noise is the signal.” The technique used now makes it possible to re-evaluate even older, seemingly useless data and to discover signals that had previously remained hidden.
More information: Eric Kleinherbers et al, Unraveling spin dynamics from charge fluctuations, Physical Review Research (2023). DOI: 10.1103/PhysRevResearch.5.043103
Featured image: A look inside the open cryostat: In operation, the slide with the mounted sample is analyzed in a vacuum at about -270°C. Credit: Hendrik Mannel
Thales Group, a global leader in technology innovation, is channelling significant resources into the realm of quantum technologies, recognizing their transformative potential across various sectors. As part of this strategic focus, the company is leveraging quantum advancements to revolutionize fields such as cybersecurity, aerospace, transportation, and defense, aiming to bring about groundbreaking changes in both societal and industrial landscapes.
At the UK National Quantum Technologies Showcase held earlier this month, Thales’ top executives, Dr. Bernhard Quendt, Group Chief Technical Officer, and Dr. Paul Gosling, UK Chief Technical Officer, joined a gathering of industry leaders, academics, government figures, and investors. This event was a pivotal platform for examining the rapid progression of quantum technology and its commercial applications in the UK, a prominent hub for quantum innovation in Europe.
The showcase, orchestrated by Innovate UK and the Engineering and Physical Sciences Research Council (EPSRC), in partnership with the UK National Quantum Technologies Programme, served as a fertile ground for discussions on the latest quantum breakthroughs. These discussions spanned a diverse range of fields, including automotive, healthcare, infrastructure, communications, cyber, and defense, highlighting the versatile impact of quantum technologies.
Here is what Thales executives had to say:
Dr Gosling:
“The first generation of quantum technology gave us the transistor, microchip, laser and MRI scanner to name but a few. These all had a remarkable, but largely unanticipated impact on society.
We are now on the verge of the next generation of quantum technology that can deliver unprecedented computing power and sensors with a far greater sensitivity than ever before. Many of these next generation quantum devices have already been demonstrated in the laboratory.
The challenge in the next few years is to accelerate the ability to incorporate these new quantum devices into systems, work out how to exploit them and in the case of quantum computing, protect our data against computers that will be able to crack existing encryption in matters of minutes instead of years.
Importantly, the technology needs to move from the lab to production so we need to develop the local manufacturing base which will allow ready access to the best devices on the market.
As with the first generation of quantum technologies, the impact on society will likely be significant and we probably can’t fully appreciate at this point the extent to which it will impact the lives of future generations.
It is for this reason that countries like the UK and companies such as Thales see investment in and mastery of quantum as a key strategic topic.”
Dr Quendt:
“Thales is delighted to participate to this key quantum event in the UK. We are the only European player present and leading in the three areas of quantum: sensors, communications and algorithms.
This is made possible thanks to the significant skills of the employees, their passion for quantum, a considerable amount of patents and increasing investment of the Group in quantum technologies.”
Thales’ active participation and investment in quantum technologies underscore the company’s commitment to being at the forefront of emerging tech trends. By deeply engaging in these critical discussions, Thales aims to not only contribute to but also shape the direction of quantum technology development, ensuring its effective integration into future solutions that will redefine our society and industries.
A team from Tokyo Institute of Technology and RIKEN has published a study in Nature Physics revealing significant noise correlations between pairs of silicon spin qubits, which could impact the development of scalable quantum processors.
The research focused on measuring and quantifying the correlations of noise that may impair the performance of quantum processors by increasing error rates, a crucial aspect considering the millions of qubits required for a functional quantum computer.
Utilizing a novel Bayesian estimation technique, the researchers confirmed strong noise correlations that persist over distance, underscoring the need for new methods to manage such noise in dense qubit arrays for future semiconductor-based quantum computing systems.
UNIVERSITY RESEARCH NEWS — TOKYO/November 3, 2023 — A research team at the Tokyo Institute of Technology and RIKEN recently set out to reliably quantify the correlations between the noise produced by pairs of semiconductor-based qubits, which are very appealing for the development of scalable quantum processors. Their paper, published in Nature Physics, unveiled strong interqubit noise correlations between a pair of neighboring silicon spin qubits.
“A useful quantum computer would practically require millions of densely packed, well-controlled qubits with errors not only small but also sufficiently uncorrelated,” Jun Yoneda, one of the researchers who carried out the study, told Phys.org. “We set out to address the potentially serious issue of error correlation in silicon qubits, as they have become a compelling platform for large quantum computations otherwise.”
Fabricating highly performing quantum processors based on many closely positioned silicon qubits has so far proved challenging. These systems would exhibit noise that is correlated between different qubits. This reduces the devices’ fault tolerance, increasing their error rate and thus impairing their performance.
As part of their recent study, Yoneda and his colleagues set out to explore the extent of these interqubit noise correlations, in the hope of informing the future development of semiconductor-based quantum computing systems. To do this, they analyzed and tried to quantify the correlation between the noise seen by two silicon-based qubits that were placed 100 nm away from each other.
“Errors in silicon spin qubits are dominated by fluctuations of the qubit energy, that is, the energy difference between the spin-up and -down states,” Yoneda explained. “We measured the simultaneous time evolution of qubit energies and assessed the ‘degree of similarity’ between the two time traces via a quantity called the cross power spectral density.”
The researchers subsequently used a Bayesian estimation technique they developed as part of their previous research work, which is designed to give the probability distributions of cross power spectral densities. This technique allowed them to validate the statistical relevance of the correlations they observed, confirming that the two qubits were subject to strongly correlated noise.
“We observed strong noise correlations between silicon qubits — with a correlation strength as large as 0.7 at some frequencies,” Yoneda said. “Such correlations due to electrical noise are unlikely to decay quickly with distance, so we are now keenly aware that error correlation needs to be taken seriously in dense qubit arrays in silicon. We also showed that noise correlation analysis provides novel insights into the source of qubit noise.”
The statistical methods employed by this team of researchers is unique and powerful, as contrarily to conventional approaches, it requires no prior knowledge of the auto-spectrum (e.g., 1/f) to assess and quantify qubit noise. Overall, the findings of this recent work confirm the challenges associated with noise correlation between closely situated silicon qubits, highlighting the need to devise new approaches to suppress or mitigate noise in semiconductor-based quantum computers.
“Our future research will include investigating how far the correlation will extend in a qubit array, leveraging the methods of including cross correlations in noise analysis that we pioneered here experimentally,” Yoneda added. “This is a critical question concerning fault-tolerance, as well as understanding of the noise source.”
Herbert Fotso, a physicist at the University of Buffalo, received a $225,967 grant from the Department of Energy to study how disorder within quantum materials affects their properties, challenging the common goal to avoid imperfections in such materials.
The research, in collaboration with Hanna Terletska from Middle Tennessee State University, will develop computational models to understand the interaction between electron behaviors and structural disorder in materials, which can lead to unexpected conductive properties.
These models will be made open-source, facilitating global research efficiency and aiding in the understanding and development of materials for future technologies such as quantum computing.
UNIVERSITY RESEARCH NEWS —Buffalo, NY/November 3, 2023 —In the field of materials science, disorder gets a bad rap.
Disorder — imperfections in a material’s structure — is typically something to be avoided, especially when synthesizing quantum materials whose exotic properties offer great potential for superconductors and ultrafast computers.
Yet every material has some amount of disorder, and for some, disorder may explain why they exhibit their exciting properties in the first place.
UB condensed matter physicist Herbert Fotso is principal investigator on a recent $225,967 grant from the Department of Energy to study quantum materials and how disorder affects their behavior.
“We hope to fill a vacuum of information that can enable breakthroughs in materials science and even guide the synthesis of new materials,” says Fotso, associate professor in the Department of Physics, College of Arts and Sciences.
In this collaborative project with Hanna Terletska, associate professor in the Department of Physics and Astronomy at Middle Tennessee State University, Fotso will create computational models to better understand the role of disorder in quantum materials that also have strong interactions between their electrons when driven away from equilibrium.
“Very often, studies of quantum materials have considered strong interaction between electrons and disorder separately,” Fotso says. “We’re proposing methods to study the interplay of interaction and disorder, evaluating what happens when both of these are important in a given material.”
For example, metal-to-insulator transitions can be driven by both disorder and interaction. Some materials that should conduct electricity instead act as insulators due to some level of disorder. In other cases, a material may act as an insulator because the interactions between its electrons are so strong that they cannot move freely.
“So what happens when these two elements are present in the same material? This interplay gives rise to a number of rather interesting and sometimes surprising behaviors,” Fotso says.
Typically, scientists analyze a material’s properties by increasing its charge concentration. However, this process often also creates some disorder in the material. In some cases, disorder may ultimately be more responsible for the observed properties than the increased charge concentration.
Fotso says precise, well-behaved materials are the foundation of materials science and the development of materials for quantum computing in particular, so scientists need an accurate understanding of why materials behave the way they do.
“When you’re running experiments, you want to be able to anticipate your results. Those expectations are guided by theory, and that theory must factor in the key parameters of the system,” he says. “If you don’t have all of the key parameters, you will miss out on what exactly is happening in that material.”
Fotso and Terletska’s computational models will be released as open-source tools, allowing other research groups to take advantage and enable studies of quantum materials that were previously inaccessible.
“Ideally, as a community, we do not want research groups across the world to be duplicating efforts because time is valuable,” says Fotso, who joined the UB faculty in 2022. “Increasingly, many of the problems that are relevant to future technologies will involve many different subfields of not only science, but even subfields within physics and within condensed matter physics.”
Researchers at Delft University of Technology have successfully split a Cooper pair into individual electrons and maintained them within a hybrid quantum dot system, as reported in their study published in Physical Review Letters.
The research aims to further investigate the properties of these split electrons, which could have implications for understanding superconductivity and quantum entanglement.
The team employed a novel technique involving electric fields, rather than electrical currents, to control the electrons.
UNIVERSITY RESEARCH NEWS — Delft, Netherland/November 6, 2023 — Researchers at Delft University of Technology (TU Delft) recently demonstrated the controllable splitting of a Copper pair into its two constituent electrons within a hybrid quantum dot system, holding onto them after the split. Their paper, published in Physical Review Letters, could open new avenues for the study of superconductivity and entanglement in quantum dot systems.
“This research was motivated by the fact that Cooper pairs, the fundamental ingredients of superconductivity that carry electrical current with no resistance, are formed by pairs of electrons that are expected to be perfectly quantum entangled,” Christian Prosko, one of the authors of the paper, told Phys.org.
“Previous work by numerous research groups has gone into splitting Cooper pairs into their two constituent electrons to check for this entanglement, but we hoped to build on these experiments by fabricating a device in which one could ‘hold on’ to two electrons after splitting a pair to investigate their properties further.”
While researchers have identified multiple ways to check if two particles are quantum entangled, retaining the particles after they are split can greatly advance these efforts. Leo P. Kouwenhoven’s lab at TU Delft specializes in techniques that exploit microwave resonators to probe the movement of electrons, enabling the control of electrons in devices without having to pass electrical currents through them.
“In our case, we hold on to them by ensuring they are stuck in quantum dots, regions of a semiconducting material designed to behave like a box for holding electrons,” Prosko said.
“At the same time, we wanted to demonstrate a method for actually detecting the moment when a Cooper pair is split, so we designed a detector out of quantum dots which can sense when an individual electron jumps on or off of it. I should note here that around the time of this work, another group observed the splitting of single Cooper pairs.”
Conventional devices to split electrons bound in Cooper pairs consist of a superconductor-based electrical contact and two ordinary metallic contacts, separated by quantum dots. Quantum dots typically only receive one electron at a time, while electrical current flowing through semiconductors is carried by electron Cooper pairs.
“If you force a current between the superconductor and the metal contacts, Cooper pairs have no choice but to split in order to make it through the quantum dots towards the other metal terminals of your circuit,” Prosko explained. “In our case, we replaced the superconducting lead with an isolated chunk of superconductor and got rid of the electrical contacts entirely. By applying electric fields to the quantum dots and superconductor, we were able to ‘push’ a single Cooper pair out of the superconductor, forcing it to split onto the two quantum dots.”
Due to its unique design and the absence of electrical contacts, the hybrid quantum dot system created by Prosko and his colleagues has no electrical current flowing through it. When they ‘pushed’ a single Cooper pair out of the superconductor, the electrons became isolated onto the quantum dots. Through this process, the researchers were able to hold on to split electrons that were previously part of a single Cooper pair.
“Our recent work consisted of two parts: Splitting a single Cooper pair and holding on to the resulting electrons, and separately demonstrating a method for detecting single electrons jumping on to a quantum dot without external charge sensors,” Prosko said. “These two achievements together would allow one to cause Cooper pair splitting events and detect the emerging electrons in real time, moving us one step closer to testing the quantum entanglement of electrons which is so fundamental to superconductivity.”
Some of the authors of this paper have now completed their Ph.D. at TU Delft and started working at other institutes and companies. In the future, these researchers and other students who are still part Kouwenhoven’s lab will continue exploring superconductivity, quantum entanglement, and quantum computing.
“We hope our research groups will continue combining the single Cooper pair splitting technique with parity sensors that can also detect the magnetic spin of electrons,” Prosko added.
More information: Damaz de Jong et al, Controllable Single Cooper Pair Splitting in Hybrid Quantum Dot Systems, Physical Review Letters (2023). DOI: 10.1103/PhysRevLett.131.157001.
Featured image: An abstract diagram of two types of Cooper pair splitters. The conventional Cooper pair splitter (including the faded parts of the diagram) consists of a superconducting contact separated from two ordinary metal contacts by two quantum dots. When a current is applied across the circuit, Cooper pairs are forced by the quantum dots to split before leaving the device into the metal contacts. In our approach (without the faded parts), there are no contacts and the superconductor is an isolated piece of material. By applying electric fields with voltages V_L and V_R to the quantum dots, we can pull electrons onto the dots by splitting a Cooper pair, after which the electrons stably remain on the dots. Credit: de Jong et al.
The National Institute of Information and Communications Technology has developed a Superconducting Wide-Strip Photon Detector (SWSPD), featuring a novel structure that allows for highly efficient photon detection with a strip width over 200 times wider than conventional Superconducting NanoStrip Photon Detectors (SNSPDs).
The SWSPD is poised for application in various cutting-edge technologies, including quantum information communication and quantum computers, potentially accelerating their societal implementation.
Published in Optica Quantum, the research outlines the SWSPD’s comparable performance to existing technologies, with a 78% detection efficiency in the telecommunication wavelength band and improved timing jitter.
RESEARCH NEWS — Japan/October 31, 2023 — Researchers from the National Institute of Information and Communications Technology has invented a novel structure in a superconducting strip photon detector that enables highly efficient photon detection even with a wide strip, and succeeded in developing the world’s first Superconducting Wide-Strip Photon Detector (SWSPD).
The strip width of the detector is over 200 times wider than that of the conventional Superconducting NanoStrip Photon Detectors (SNSPDs). This technology can help to solve the problems of low productivity and polarization dependence that exist in conventional SNSPDs. The new SWSPD is expected to be applied into various advanced technologies such as quantum information communication and quantum computers, enabling early social implementation of these advanced technologies.
The work is published in the journal Optica Quantum.
Photon detection technology is a strategic core technology to bring about an innovation in a wide range of advanced technology fields, including quantum information communication and quantum computing, which are currently undergoing intense research and development on a global scale, and also live cell fluorescent observation, deep space optical communication, laser sensing, and more.
The NICT research team has developed a SNSPD with a strip width of 100 nm or less. They have successfully achieved high performance surpassing other photon detectors, and have demonstrated its usefulness by applying it to quantum information communication technology. However, the fabrication of SNSPDs requires the formation of nanostrip structures using advanced nanofabrication technology, which causes variations in detector performance and hinders productivity improvement. In addition, the presence of polarization dependence due to the superconducting nanostrip meandering structure has also limited the application range as a photon detector.
In this work, NICT invented a novel structure called “High Critical Current Bank (HCCB) structure” that enables highly efficient photon detection even if the strip width is widened in the superconducting strip photon detector, and succeeded in developing a SWSPD with a width of 20 micrometers — over 200 times wider than the conventional nanostrip photon detector — and achieved high-performance operation for the first time in the world.
The nanostrip type developed by NICT required the formation of extremely long superconducting nanostrips with a strip width of 100 nm or less in a meandering shape. The wide strip type can now be formed with only single short straight superconducting strip.
This SWSPD does not require nanofabrication technology and can be fabricated by highly productive general-purpose photolithography technology. In addition, since the strip width is wider than the incident light spot irradiated from the optical fiber, it is possible to eliminate the polarization dependence seen in the nanostrip type detector.
As a result of performance evaluation of this detector, the detection efficiency in the telecommunication wavelength band (λ=1,550 nm) measured 78%, which is comparable to the 81% of the nanostrip type. Furthermore, the timing jitter showed better numerical values than the nanostrip type.
This achievement enables the fabrication of photon detectors with higher productivity and superior performance and features compared to the nanostrip type that has been positioned as an indispensable photon detection technology in advanced technology fields such as quantum information communication. Such technology is expected to be applied to various quantum information communication technologies and to be an important basic technology for realizing networked quantum computers promoted in JST Moonshot Goal 6.
In the future, the team will further explore the HCCB structure in the SWSPD, to detect photons with high efficiency not only in the telecommunication wavelength band, but also in a wide wavelength band from the visible to the mid-infrared. Furthermore, they will also try further expansion of the size of the photon receiving area for expanding the applications such as deep space optical communication technology, laser sensing, live cell observation and more.
More information: Masahiro Yabuno et al, Superconducting wide strip photon detector with high critical current bank structure, Optica Quantum (2023). DOI: 10.1364/OPTICAQ.497675
Provided by National Institute of Information and Communications Technology (NICT)
Featured image: Developed Superconducting Wide-Strip Photon Detector (SWSPD). Credit: National Institute of Information and Communications Technology (NICT)
A new research project named COSMOS, funded by the Engineering and Physical Sciences Research Council and led by UCL in collaboration with the University of Warwick and other institutions aims to develop a universal software framework for quantum dynamics simulations.
This initiative is set to remove the barriers posed by the current individualized approach of research groups using their own custom-made software, making it difficult to share improvements and ideas across different teams.
The universal software will facilitate a broader range of scientists globally in using computer simulations to delve into the quantum world more efficiently.
UNIVERSITY RESEARCH NEWS — Warwick, UK/October 27, 2023 — For the first time, scientists will develop a universal software framework for simulations, removing many barriers that exist to achieving a deeper understanding across the quantum world.
Scientists use powerful sources of light to study tiny particles, atoms and molecules that make up the matter around us — known as the quantum domain. These experiments can be used to answer important questions about how particles behave in chemical reactions, material properties, and new quantum technologies.
To understand the results of the experiments, computer simulations are crucial. The computer-generated virtual model shows how these tiny particles move according to the rules of quantum physics. Using newly developed quantum simulations, researchers better predict and understand what’s happening to molecules during experiments.
The problem is that most research groups use their own custom-made software for their studies. This individual approach means it is difficult for scientists to use ideas from one group to improve the methods of another group.
To address this, a new research project called COSMOS, funded by the Engineering and Physical Sciences Research Council (ESPRC), led by UCL and including researchers at The University of Warwick, will develop a unified code for quantum dynamics simulations suitable for use by both computational and experimental researchers.
This universal software will enable a wider group of scientists worldwide to use computer simulations to explore the quantum world more efficiently, and it will aid researchers across a broad range of research areas to understand state-of-the art experiments and exploit quantum effects by designing new molecules and materials.
Professor Scott Habershon, Department of Chemistry, University of Warwick, a Principal Investigator for the research, said: “Many important new technologies — like quantum computing and artificial photosynthesis (creating sustainable energy from sunlight) — are based on understanding and controlling the dynamics of electrons, atoms and molecules. Computer modelling of these quantum processes has always been very challenging — but this exciting new project will allow our team to develop new ideas and new software to meet this challenge head-on.”
Lead researcher Professor Graham Worth, UCL, added: “I am very excited to be heading this international team. The project will be a big challenge and I am looking forward to seeing how we can combine our knowledge and ideas to provide a step-change in the way we can describe, visualise and exploit quantum processes.”
By supporting a large, yet integrated cohort of early-career researchers, this programme grant will provide an enormous acceleration to developments in the quantum domain, positioning the UK as a global leader in this domain as we move from the era of classical computation and simulation into the quantum era of the coming decades.
Other Principal Investigators on the project are Dr. Basile Curchod (University of Bristol), Professor Adam Kirrander (University of Oxford), Professor Tom Penfold (Newcastle University) and Professor Dmitry Shalashilin (University of Leeds).
Professor Andrew Orr-Ewing, University of Bristol, commented: “New advances of the type offered by the COSMOS project are essential for the detailed interpretation of experimental data from ultrafast spectroscopy studies of photochemical processes important in the Earth’s atmosphere or in biological systems.
“The COSMOS code will transform how we obtain new insights from our experimental results, and it will allow us to study ever more complex photochemical processes.”
Media contact
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A collaborative research study involving scientists from SISSA, the University of Trento, and the University of Milano-Bicocca has explored the potential of combining quantum and traditional computing methods to enhance computational performance in simulating dense polymer mixtures, utilizing a mathematical approach known as QUBO.
The quantum annealers used for this approach showed a significant boost in performance compared to traditional techniques, with the methodology also proving effective when applied to conventional computers.
The study, led by Cristian Micheletti, utilized QUBO to overcome the limitations of Monte Carlo simulation techniques, which become less efficient as system density and size increase and could lead to a better understanding and simulation of complex systems, such as the organization of chromosomes in the cell nucleus, without requiring extensive computational resources.
UNIVERSITY RESEARCH NEWS — Italy/October 25, 2023 — The advent of quantum computing is opening previously unimaginable perspectives for solving problems deemed beyond the reach of conventional computers, from cryptography and pharmacology to the physical and chemical properties of molecules and materials. However, the computational capabilities of present-day quantum computers are still relatively limited. A newly published study in Science Advances fosters an unexpected alliance between the methods used in quantum and traditional computing. The research team, formed by Cristian Micheletti and Francesco Slongo of SISSA in Trieste, Philipp Hauke of the University of Trento, and Pietro Faccioli of the University of Milano-Bicocca, used a mathematical approach called QUBO (from “Quadratic Unconstraint Binary Optimization”) that is ideally suited for specific quantum computers, called “quantum annealers”. The study harnessed the QUBO approach to simulate in a radically new way dense polymer mixtures, which are complex physical systems central to biology and material science. The result? A major boost in computational performance was obtained with the quantum computers compared to traditional techniques, thus providing a significant example of the vast potential of these emerging technologies. Remarkably, the QUBO approach proved particularly effective even when adopted on conventional computers, enabling researchers to discover surprising properties of the simulated polymer mixtures. The implications can be far-reaching given that the approach used in the study is naturally suited to be transferred to many other molecular systems.
A new perspective inspired by quantum computing research
“Simulation techniques known as ‘Monte Carlo’ have long been among the most powerful, elegant, and versatile methods for studying complex systems, such as synthetic polymers or biological ones, such as DNA” explains Cristian Micheletti, who coordinated the study. “However, the efficiency of these methods drops as the system density and size increase. For this reason, studying realistic systems, such as the organization of chromosomes in the cell nucleus, requires huge investments of computational resources.” Francesco Slongo, SISSA doctoral student and first author of the study, continues: “Quantum computers promise major boosts of computational performance, albeit with the inevitable limitations of novel technologies. And this is where the new simulation strategy comes in, which is ideally suited to today’s pioneering quantum computers, and yet can be successfully transferred even to traditional computers.”
An unexpected boost for classical simulations
As Philipp Hauke and Pietro Faccioli note, “Currently, there already exist quantum machines dedicated to solving QUBO, and they can be highly effective. We reformulated conventional polymer models in the QUBO framework to optimally exploit such machines. Surprisingly, the QUBO reformulation also proved advantageous on traditional computers, allowing faster simulation of dense polymers than with established methods. Thanks to this, we established previously unknown properties for these systems, all using standard computers.”
Implications, challenges, and future directions
It has happened before that physical models created to take full advantage of innovative computing technologies have become so successful to be eventually transferred to different areas. The best-known case is that of lattice-based fluid models designed for 1990s supercomputers but now widely used for many other systems and types of computers. The study in Science Advances provides a further example, demonstrating how methodologies inspired by quantum computing can pave the way for exploring new materials and understanding the workings of molecular systems of biological interest.
The research was supported by NRRP grant CN 00000013 CN-HPC, M4C2I1.4, spoke 7, funded by NextGenerationEU, and ERC starting grant StrEnQTh (project ID 804305). This project was funded by the European Union under the Horizon Europe programme — Grant Agreement 101080086 — NeQST. However, the views and opinions expressed are solely those of the author(s) and do not necessarily reflect those of the European Union or the European Commission. Neither the European Union nor the authority that granted the funding can be held responsible.
Argonne National Laboratory, led by the U.S. Department of Energy, has significantly extended the coherence time of a novel type of qubit to 0.1 milliseconds, nearly a thousand times better than previous records, paving the way for advancements in quantum computing.
The qubits, known as charge qubits, are more straightforward in fabrication and operation, offering compatibility with existing computer infrastructures and potential cost-effectiveness for large-scale quantum computers.
They are encoded in an electron’s charge states and protected from environmental disruption when placed on a solid-neon surface.
RESEARCH PRESS RELEASE — Argonne National Laboratory/October 26, 2023 — Coherence stands as a pillar of effective communication, whether it is in writing, speaking or information processing. This principle extends to quantum bits, or qubits, the building blocks of quantum computing. A quantum computer could one day tackle previously insurmountable challenges in climate prediction, material design, drug discovery and more.
A team led by the U.S. Department of Energy’s (DOE) Argonne National Laboratory has achieved a major milestone toward future quantum computing. They have extended the coherence time for their novel type of qubit to an impressive 0.1 milliseconds — nearly a thousand times better than the previous record.
“Rather than 10 to 100 operations over the coherence times of conventional electron charge qubits, our qubits can perform 10,000 with very high precision and speed.” — Dafei Jin, professor at the University of Notre Dame with a joint appointment at Argonne’s Center for Nanoscale Materials.
In everyday life, 0.1 milliseconds is as fleeting as a blink of an eye. However, in the quantum world, it represents a long enough window for a qubit to perform many thousands of operations.
Unlike classical bits, qubits seemingly can exist in both states, 0 and 1. For any working qubit, maintaining this mixed state for a sufficiently long coherence time is imperative. The challenge is to safeguard the qubit against the constant barrage of disruptive noise from the surrounding environment.
The team’s qubits encode quantum information in the electron’s motional (charge) states. Because of that, they are called charge qubits.
“Among various existing qubits, electron charge qubits are especially attractive because of their simplicity in fabrication and operation, as well as compatibility with existing infrastructures for classical computers,” said Dafei Jin, a professor at the University of Notre Dame with a joint appointment at Argonne and the lead investigator of the project. “This simplicity should translate into low cost in building and running large-scale quantum computers.”
Jin is a former staff scientist at the Center for Nanoscale Materials (CNM), a DOE Office of Science user facility at Argonne. While there, he led the discovery of their new type of qubit, reported last year.
The team’s qubit is a single electron trapped on an ultraclean solid-neon surface in a vacuum. The neon is important because it resists disturbance from the surrounding environment. Neon is one of a handful of elements that do not react with other elements. The neon platform keeps the electron qubit protected and inherently guarantees a long coherence time.
“Thanks to the small footprint of single electrons on solid neon, qubits made with them are more compact and promising for scaling up to multiple linked qubits,” said Xu Han, an assistant scientist in CNM with a joint appointment at the Pritzker School of Molecular Engineering at the University of Chicago. “These attributes, along with coherence time, make our electron qubit exceptionally compelling.”
Following continued experimental optimization, the team not only improved the quality of the neon surface but also significantly reduced disruptive signals. As reported in Nature Physics, their work paid off with a coherence time of 0.1 milliseconds. That is about a thousand-fold increase from the initial 0.1 microseconds.
“The long lifetime of our electron qubit allows us to control and read out the single qubit states with very high fidelity,” said Xinhao Li, a postdoctoral appointee at Argonne and the co-first author of the paper. This time is well above the requirements for quantum computing.
“Rather than 10 to 100 operations over the coherence times of conventional electron charge qubits, our qubits can perform 10,000 with very high precision and speed,” Jin said.
Yet another important attribute of a qubit is its scalability to link with many other qubits. The team achieved a significant milestone by showing that two-electron qubits can couple to the same superconducting circuit such that information can be transferred between them through the circuit. This marks a pivotal stride toward two-qubit entanglement, a critical aspect of quantum computing.
The team has not yet fully optimized their electron qubit and will continue to work on extending the coherence time even further as well as entangling two or more qubits.
The work was funded by the DOE Office of Basic Energy Sciences; a Laboratory Directed Research and Development award from Argonne; and Q-NEXT, a DOE Energy National Quantum Information Science Research Center headquartered at Argonne. Additional funding came from the Julian Schwinger Foundation for Physics Research and National Science Foundation.
This research was published in Nature Physics. In addition to Jin, Han and Li, Argonne contributors include postdocs Xianjing Zhou and Qianfan Chen. Other contributors include co-corresponding author David I. Schuster, a former physics professor at the University of Chicago now at Stanford University, and Xufeng Zhang, a former staff scientist at CNM and now a professor at Northeastern University. Also listed as authors are Gerwin Koolstra, Ge Yang, Brennan Dizdar, Yizhong Huang and Christopher S. Wang.
The collaborating institutions include Lawrence Berkeley National Laboratory, Massachusetts Institute of Technology, Northeastern University, Stanford University, the University of Chicago and the University of Notre Dame.
About Argonne’s Center for Nanoscale Materials
The Center for Nanoscale Materials is one of the five DOE Nanoscale Science Research Centers, premier national user facilities for interdisciplinary research at the nanoscale supported by the DOE Office of Science. Together the NSRCs comprise a suite of complementary facilities that provide researchers with state-of-the-art capabilities to fabricate, process, characterize and model nanoscale materials, and constitute the largest infrastructure investment of the National Nanotechnology Initiative. The NSRCs are located at DOE’s Argonne, Brookhaven, Lawrence Berkeley, Oak Ridge, Sandia and Los Alamos National Laboratories. For more information about the DOE NSRCs, please visit https://science.osti.gov/User-Facilities/User-Facilities-at-a-Glance.
Argonne National Laboratory seeks solutions to pressing national problems in science and technology. The nation’s first national laboratory, Argonne conducts leading-edge basic and applied scientific research in virtually every scientific discipline. Argonne researchers work closely with researchers from hundreds of companies, universities, and federal, state and municipal agencies to help them solve their specific problems, advance America’s scientific leadership and prepare the nation for a better future. With employees from more than 60 nations, Argonne is managed by UChicago Argonne, LLC for the U.S. Department of Energy’s Office of Science.
The U.S. Department of Energy’s Office of Science is the single largest supporter of basic research in the physical sciences in the United States and is working to address some of the most pressing challenges of our time. For more information, visit https://energy.gov/science.
PSIRCH, a quantum technology executive search division, has announced its partnership with the University of Maryland’s Mid-Atlantic Quantum Alliance and has become the newest member of this prestigious quantum technology research and development ecosystem, following their establishment of a new East Coast location.
The alliance boasts participation from major entities such as Johns Hopkins, MITRE, IBM, Lockheed Martin, Booz Allen Hamilton, Amazon Web Services, and others, positioning PSIRCH in a strategic network for fostering quantum workforce development, engaging with local clients and collaborators, and ramping up these efforts in the future.
The Mid-Atlantic Quantum Alliance, home to the National Quantum Laboratory (QLab) and a network of over 400 quantum scientists and engineers, 15 academic institutions, and numerous startups provides PSIRCH with direct access to a vast pool of quantum talent, which is anticipated to greatly benefit their clients and contribute back to the quantum community.
PRESS RELEASE — PSIRCH, Arlington, VA/October 2, 2023 — Following the establishment of its new East Coast location, PSIRCH is proud to announce its new partnership with the University of Maryland’s Mid-Atlantic Quantum Alliance https://mqa.umd.edu/ and has now joined the prestigious alliance as its newest member.
Joining the ranks of other members of the alliance, including Johns Hopkins, MITRE, IBM, Lockheed Martin, Booz Allen Hamilton, Amazon Web Services, and others, PSIRCH aptly anticipates a strong positive value in the partnership, and in becoming a duly committed
participant in arguably the strongest ecosystem globally for quantum technology research and development.
PSIRCH, the world’s first quantum technology executive search division of an established firm has already commenced efforts to help grow and develop the prowess of the quantum workforce in this regional hub, engage with local quantum clients and collaborators, and plans to not only continue, but also to ramp up these efforts increasingly over the coming months and years.
“We are delighted to have joined the Mid Atlantic Quantum alliance,” commented PSIRCH’s President, Shai Phillips, “not only because University of Maryland and the State of Maryland have shown enormous dedication, investment, and capability in developing quantum, but also because we feel we have a lot to offer as a steadfast participant, and vice-versa. Maryland has been called the “Capital of Quantum”, and we can see why.”
The Mid-Atlantic Quantum Alliance, launched in 2020 to accelerate quantum science and enhance the region’s primacy in a field that promises to revolutionize society, brings together world-leading quantum expertise in academia, industry, government agencies, laboratories and research centers with a presence in the region.
Home to the National Quantum Laboratory (QLab), a joint venture between IonQ and the University of Maryland, which officially opened last month, the institution boasts a wealth of talent that feeds into the Mid-Atlantic Quantum Alliance’s network — one of the densest
networks of quantum talent worldwide, with over 400 quantum scientists and engineers, a large pool of entrepreneurs and quantum startups, and the involvement of 15 academic institutions. “For a quantum technology executive search outfit like us, direct access to such a vast and high-caliber talent pool will serve our clients extremely well,” expressed Phillips, “and we’re confident we can transfer that value not only to our clients, but also return it back, with interest, to the ecosystem itself.”
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