Shimon Kolkowitz awarded two grants to push optical atomic clocks past the standard quantum limit
Optical atomic clocks are already the gold standard for precision timekeeping, keeping time so accurately that they would only lose one second every 14 billion years. Still, they could be made to be even more precise if they could be pushed past the current limits imposed on them by quantum mechanics.
With two new grants from the U.S. Army Research Office, an element of the U.S. Army Combat Capabilities Development Command’s Army Research Laboratory, UW–Madison physics professor Shimon Kolkowitz proposes to introduce quantum entanglement — where atoms interact with each other even when physically distant — to optical atomic clocks. The improved clocks would allow researchers to ask questions about fundamental physics, and they have applications in improving quantum computing and GPS.
Atomic clocks are so precise because they take advantage of the natural vibration frequencies of atoms, which are identical for all atoms of a particular element. These clocks operate at or near the standard quantum limit, a fundamental limit on performance imposed on clocks where the atoms are all independent of each other. The only way to push the clocks past that limit is to achieve entangled states, strange quantum states where the atoms are no longer independent and they become intertwined.
“That turns out to be hard for a number of reasons. Entanglement requires these atoms to interact with each other, but a good clock requires them not to interact with each other or anything else,” Kolkowitz says. “So, you need to engineer a situation where you can make the atoms interact strongly, but you can also switch those interactions off. And those are some of the same requirements that are necessary for quantum computing.”
Kolkowitz is already building an optical atomic clock in his lab, albeit one that is not yet using entangled states. To make the clock, they first laser-cool strontium atoms to one millionth of one degree Celsius above absolute zero, then load the atoms into an optical lattice. In the lattice, the atoms are separated into what is effectively a tiny stack of pancakes — each atom can move around within their own flat disk, but they cannot jump into another pancake.
Though the atoms’ are stuck in their own pancake, they can interact with each other if their electrons are highly excited. This type of atom, known as Rydberg atoms, becomes close to one million times larger than an unexcited counterpart because the excited electron can be microns away from the nucleus.
“It’s kind of crazy that a single atom can be that big, and when you make them that much bigger, they interact much more strongly with each other than they do in their ground states,” Kolkowitz says. “Basically it means you can go from the atoms not interacting at all to interacting very strongly. That’s exactly what you want for quantum computing, and it’s what you want for this atomic clock.”
With the two ARO grants, Kolkowitz expects to generate Rydberg atoms in his lab’s atomic clock. One of the grants, a Defense University Research Instrumentation Program (DURIP), will fund the specialized UV laser that generates the high energy photons needed to excite the atoms into the highly excited Rydberg states. The second grant will fund personnel and other supplies. Kolkowitz will collaborate with UW–Madison physics professor Mark Saffman, who, along with physics professor Thad Walker, pioneered the use of Rydberg atoms for quantum computing.
In addition to being useful for developing new approaches to ask questions about fundamental physics in his research lab, these ultraprecise atomic clocks are of interest to the Department of Defense for atomic clock-based technologies such as GPS, and because they can be used to precisely map Earth’s gravity.
Researchers awarded Department of Energy Quantum Information Science Grant
Three UW–Madison physics professors and their colleagues have been awarded a U.S. Department of Energy (DOE) High Energy Physics Quantum Information Science award for an interdisciplinary collaboration between theoretical and experimental physicists and experts on quantum algorithms.
The grant, entitled “Detection of dark matter and neutrinos enhanced through quantum information,” will bring a total of $2.3 million directly to UW-Madison. Physics faculty include principal investigator Baha Balantekin as well as Mark Saffman, and Sue Coppersmith. Collaborators on the grant include Kim Palladino at the University of Oxford, Peter Love at Tufts University, and Calvin Johnson at San Diego State University.
With the funding, the researchers plan to use a quantum simulator to calculate the detector response to dark matter particles and neutrinos. The simulator to be used is an array of 121 neutral atom qubits currently being developed by Saffman’s group. Much of the research plan is to understand and mitigate the behavior of the neutral atom array so that high accuracy and precision calculations can be performed. The primary goal of this project is to apply lessons from the quantum information theory in high energy physics, while a secondary goal is to contribute to the development of quantum information theory itself.
Mark Friesen promoted to Distinguished Scientist
Congratulations to Mark Friesen on his promotion to Distinguished Scientist! The distinguished title is the highest title available to an academic staff member at UW–Madison.
Friesen joined the physics department in 2004 as an associate scientist, and has been with UW–Madison since 1998, when he began a postdoc in the Materials Sciences and Engineering department. His main research effort at UW–Madison has been related to silicon quantum dot quantum computing, in collaboration with physics professors Mark Eriksson, Sue Coppersmith, Bob Joynt, Maxim Vavilov, and others.
Friesen says his most important achievement in the department is serving as a research advisor: In 16 years with UW–Madison physics, he has advised or co-advised six postdocs, 11 Ph.D. theses, four current Ph.D. students, two M.S. theses, and several undergraduate research projects. He also has 123 peer-reviewed publications and five U.S. patents, and serves as a consultant for ColdQuanta, a quantum computing company.
“Mark is known around the world for his expertise in semiconductor-based quantum computing,” Mark Eriksson says. “He is especially well known for his calculations on how the band structure in silicon interacts with interfaces to determine the quantum states for electrons in silicon-based quantum devices.”
Congrats, Mark Friesen, on this well-deserved honor!
Surprising communication between atoms could improve quantum computing
A group of University of Wisconsin–Madison physicists has identified conditions under which relatively distant atoms communicate with each other in ways that had previously only been seen in atoms closer together — a development that could have applications to quantum computing.
The physicists’ findings, published Oct. 14 in the journal Physical Review A, open up new prospects for generating entangled atoms, the term given to atoms that share information at large distances, which are important for quantum communications and the development of quantum computers.
“Building a quantum computer is very tough, so one approach is that you build smaller modules that can talk to each other,” says Deniz Yavuz, a UW–Madison physics professor and senior author of the study. “This effect we’re seeing could be used to increase the communication between these modules.”
The scenario at hand depends on the interplay between light and the electrons that orbit atoms. An electron that has been hit with a photon of light can be excited to a higher energy state. But electrons loathe excess energy, so they quickly shed it by emitting a photon in a process known as decay. The photons atoms release have less energy than the ones that boosted the electron up — the same phenomenon that causes some chemicals to fluoresce, or some jellyfish to have a green-glowing ring.
“Now, the problem gets very interesting if you have more than one atom,” says Yavuz. “The presence of other atoms modifies the decay of each atom; they talk to each other.”
Chuanhong (Vincent) Liu named to Fall 2020 cohort of the Quantum Information Science and Engineering Network (QISE-NET)
Graduate student Chuanhong (Vincent) Liu (McDermott Group) has had his project awarded funding through QISE-NET, the Quantum Information Science and Engineering Network. Run through the University of Chicago, QISE-NET is open to any student pursuing an advanced degree in any field of quantum science. Liu and other students in his cohort earn up to three years of support, including funding, mentoring and training at annual workshops. All awardees are paired with a mentoring QISE company or national lab, at which they will complete part of their projects. Liu describes his project, below. Cecilia Vollbrecht, a grad student in Chemistry, also earned this honor. Both Liu and Volbrecht are students in the Wisconsin Quantum Institute.
The Single Flux Quantum (SFQ) digital logic family has been proposed as a scalable approach for the control of next-generation multiqubit arrays. With NIST’s strong track record in the field of SFQ digital logic and the expertise of McDermott’s lab in the superconducting qubit area, we expect to achieve high fidelity SFQ-based qubit control. The successful completion of this research program will represent a major step forward in the development of a scalable quantum-classical interface, a critical component of a fully error-corrected fault-tolerant quantum computer.
WQI team named winners in international quantum research competition
A WQI faculty team was one of 18 winners in the Innovare Advancement Center’s “Million Dollar International Quantum U Tech Accelerator” competition, which awarded a total of $1.35 million last week. The winning teams, including UW–Madison physics professors Shimon Kolkowitz and Mark Saffman, each earned $75,000 toward their proposed research.
The competition attracted nearly 250 proposals from teams across the world in the areas of quantum timing, sensing, computing and communications, and 36 teams were invited to present at the live virtual event.
Q-NEXT collaboration awarded National Quantum Initiative funding
The University of Wisconsin–Madison solidified its standing as a leader in the field of quantum information science when the U.S. Department of Energy (DOE) and the White House announced the Q-NEXT collaboration as a funded Quantum Information Science Research Center through the National Quantum Initiative Act. The five-year, $115 million collaboration was one of five Centers announced today.
Q-NEXT, a next-generation quantum science and engineering collaboration led by the DOE’s Argonne National Laboratory, brings together nearly 100 world-class researchers from three national laboratories, 10 universities including UW–Madison, and 10 leading U.S. technology companies to develop the science and technology to control and distribute quantum information.
“The main goals for Q-NEXT are first to deliver quantum interconnects — to find ways to quantum mechanically connect distant objects,” says Mark Eriksson, the John Bardeen Professor of Physics at UW–Madison and a Q-NEXT thrust lead. “And next, to establish a national resource to both develop and provide pristine materials for quantum science and technology.”
Q-NEXT will focus on three core quantum technologies:
Communication for the transmission of quantum information across long distances using quantum repeaters, enabling the establishment of “unhackable” networks for information transfer
Sensors that achieve unprecedented sensitivities with transformational applications in physics, materials, and life sciences
Processing and utilizing “test beds” both for quantum simulators and future full-stack universal quantum computers with applications in quantum simulations, cryptanalysis, and logistics optimization.
Eriksson is leading the Materials and Integration thrust, one of six Q-NEXT focus areas that features researchers from across the collaboration. This thrust aims to: develop high-coherence materials, including for silicon and superconducting qubits, which is an essential component of preserving entanglement; develop a silicon-based optical quantum memory, which is important in developing a quantum repeater; and improve color-center quantum bits, which are used in both communication and sensing.
“One of the key goals in Materials and Integration is to not just improve the materials but also to improve how you integrate those materials together so that in the end, quantum devices maintain coherence and preserve entanglement,” Eriksson says. “The integration part of the name is really important. You may have a material that on its own is really good at preserving coherence, yet you only make something useful when you integrate materials together.”
“I’m excited about Q-NEXT because of the connections and collaborations it provides to national labs, other universities, and industry partners,” Eriksson says. “When you’re talking about research, it’s those connections that often lead to the breakthroughs.
The potential impacts of Q-NEXT research include the creation of a first-ever National Quantum Devices Database that will promote the development and fabrication of next generation quantum devices as well as the development of the components and systems that enable quantum communications across distances ranging from microns to kilometers.
“This funding helps ensure that the Q-NEXT collaboration will lead the way in future developments in quantum science and engineering,” says Steve Ackerman, UW–Madison vice chancellor for research and graduate education. “Q-NEXT is the epitome of the Wisconsin Idea as we work together to transfer new quantum technologies to the marketplace and support U.S. economic competitiveness in this growing field.”
New study expands types of physics, engineering problems that can be solved by quantum computers
A well-known quantum algorithm that is useful in studying and solving problems in quantum physics can be applied to problems in classical physics, according to a new study in the journal Physical Review A from University of Wisconsin–Madison assistant professor of physics Jeff Parker.
Quantum algorithms – a set of calculations that are run on a quantum computer as opposed to a classical computer – used for solving problems in physics have mainly focused on questions in quantum physics. The new applications include a range of problems common to physics and engineering, and expands on the types of questions that can be asked in those fields.
“The reason we like quantum computers is that we think there are quantum algorithms that can solve certain kinds of problems very efficiently in ways that classical computers cannot,” Parker says. “This paper presents a new idea for a type of problem that has not been addressed directly in the literature before, but it can be solved efficiently using these same quantum computer types of algorithms.”
The type of problem Parker was investigating is known as generalized eigenvalue problems, which broadly describe trying to find the fundamental frequencies or modes of a system. Solving them is crucial to understanding common physics and engineering questions, such as the stability of a bridge’s design or, more in line with Parker’s research interests, the stability and efficiency of nuclear fusion reactors.
As the system being studied becomes more and more complex — more components moving throughout three-dimensional space — so does the numerical matrix that describes the problem. A simple eigenvalue problem can be solved with a pencil and paper, but researchers have developed computer algorithms to tackle increasingly complex ones. With the supercomputers available today, more and more difficult physics problems are finding solutions.
“If you want to solve a three-dimensional problem, it can be very complex, with a very complicated geometry,” Parker says. “You can do a lot on today’s supercomputers, but there tends to be a limit. Quantum algorithms may be able to break that limit.”
The specific quantum algorithm that Parker studied in this paper, known as quantum phase estimation, had been previously applied to so-called standard eigenvalue problems. However, no one had shown that they could be applied to the generalized eigenvalue problems that are also common in physics. Generalized eigenvalue problems introduce a second matrix that ups the mathematical complexity.
Parker took the quantum algorithm and extended it to generalized eigenvalue problems. He then looked to see what types of matrices could be used in this problem. If the matrix is sparse — meaning, if most of the numerical components that make it up are zero — it means this problem could be solved efficiently on a quantum computer.
“What I showed is that there are certain types of generalized eigenvalue problems that do lead to a sparse matrix and therefore could be efficiently solved on a quantum computer,” Parker says. “This type includes the very natural problems that often occur in physics and engineering, so this study provides motivation for applying these quantum algorithms more to generalized eigenvalue problems, because it hasn’t been a big focus so far.”
Parker emphasizes that quantum computers are in their infancy, and these classical physics problems are still best approached through classical computer algorithms.
“This study provides a step in showing that the application of a quantum algorithm to classical physics problems can be useful in the future, and the main advance here is it shows very clearly another type of problem to which quantum algorithms can be applied,” Parker says.
The study was completed in collaboration with Ilon Joseph at Lawrence Livermore National Laboratory. Funding support was provided by the U.S. Department of Energy to Lawrence Livermore National Laboratory under Contract No. DE-AC52-07NA27344 and U.S. DOE Office of Fusion Energy Sciences “Quantum Leap for Fusion Energy Sciences” (FWP SCW1680).
UW–Madison named member of new $25 million Midwest quantum science institute
As joint members of a Midwest quantum science collaboration, the University of Wisconsin–Madison, the University of Illinois at Urbana–Champaign and the University of Chicago have been named partners in a National Science Foundation Quantum Leap Challenge Institute, NSF announced Tuesday.
The five-year, $25 million NSF Quantum Leap Challenge Institute for Hybrid Quantum Architectures and Networks (HQAN) was one of three in this first round of NSF Quantum Leap funding and helps establish the region as a major hub of quantum science. HQAN’s principal investigator, Brian DeMarco, is a professor of physics at UIUC. UW–Madison professor of physics Mark Saffman and University of Chicago engineering professor Hannes Bernien are co-principal investigators.
“HQAN is very much a regional institute that will allow us to accelerate in directions in which we’ve already been headed and to start new collaborative projects between departments at UW–Madison as well as between us, the University of Illinois, and the University of Chicago.” says Saffman, who is also director of the Wisconsin Quantum Institute. “These flagship institutes are being established as part of the National Quantum Initiative Act that was funded by Congress, and it is a recognition of the strength of quantum information research at UW–Madison that we are among the first.”
Chicago Quantum Exchange, including UW–Madison, welcomes seven new partners in tech, computing and finance, to advance research and training
The Chicago Quantum Exchange, a growing intellectual hub for the research and development of quantum technology, has added to its community seven new corporate partners in computing, technology and finance that are working to bring about and primed to take advantage of the coming quantum revolution.
These new industry partners are Intel, JPMorgan Chase, Microsoft, Quantum Design, Qubitekk, Rigetti Computing, and Zurich Instruments.
The Chicago Quantum Exchange and its corporate partners advance the science and engineering necessary to build and scale quantum technologies and develop practical applications. The results of their work – precision data from quantum sensors, advanced quantum computers and their algorithms, and securely transmitted information – will transform today’s leading industries. The addition of these partners brings a total of 13 companies into the Chicago Quantum Exchange to work with scientists and engineers at universities and the national laboratories in the region.
“These new corporate partners join a robust collaboration of private and public universities, national laboratories, companies, and non-profit organizations. Together, their efforts — with federal and state support —will enhance the nation’s leading center for quantum information and engineering here in Chicago,” said University of Chicago Provost Ka Yee C. Lee.
“Developing a new technology at nature’s smallest scales requires strong partnerships with complementary expertise and significant resources. The Chicago Quantum Exchange enables us to engage leading experts, facilities and industries from around the world to advance quantum science and engineering,” said David Awschalom, the Liew Family Professor in Molecular Engineering at the University of Chicago, senior scientist at Argonne, and director of the Chicago Quantum Exchange. “Our collaborations with these companies will be crucial to speed discovery, develop quantum applications and prepare a skilled quantum workforce.”
Chicago Quantum Exchange member institutions engage with corporate partners in collaborative research efforts, joint workshops to develop new research directions, and opportunities to train future quantum engineers. The CQE has existing partnerships with Boeing, IBM, Applied Materials, Inc., Cold Quanta, HRL Laboratories, LLC, and Quantum Opus, LLC.
The CQE’s newest corporate partners include a broader set of companies ranging in interest and expertise from quantum communication hardware to quantum computing systems and controls to finance and cryptography applications.
Intel is advancing a systems-level approach to quantum research that demonstrates quantum practicality and a path to commercially viable quantum computing systems. Its research efforts – in partnership with QuTech, the quantum institute of TU Delft and TNO—include technology advancements in silicon spin qubits, control and interconnect systems for large-scale quantum systems, and quantum algorithms.
JPMorgan Chase is a leader in the field of quantum algorithms and applications for financial use cases, such as portfolio optimization, option pricing and reinforcement learning, as well as general foundational algorithms with cross-domain applicability, such as quantum search. The firm has made a significant investment in quantum computing, collaborating with multiple quantum providers and forums. Its research team is also actively working in the area of post-quantum cryptography.
Microsoft has driven advances in scalable quantum technology for nearly two decades. Their global team of physicists, computer and materials scientists, engineers, developers, and enthusiasts are collaborating with a broad community to advance a full-stack quantum computing system, develop practical solutions, enable a quantum community, and accelerate quantum workforce development.
Quantum Design manufactures automated characterization systems that allow research and exploration of new materials & devices. With the partnership, Quantum Design will support research and advanced teaching at the CQE, launching a new student laboratory for quantum measurements and the study of quantum materials.
Qubitekk develops and manufactures a variety of key components for quantum networks. Qubitekk provides entangled photon sources in its support for researchers across the CQE working on the Argonne quantum loop.
Rigetti Computing builds and delivers integrated quantum systems and offers a distinctive hybrid cloud computing access model for practical near-term applications. The company owns and operates Fab-1, the world’s first dedicated quantum integrated circuit foundry.
Zurich Instruments develops advanced instrumentation including quantum control systems that enable reliable control and measurement of superconducting qubits and silicon spin qubits. The company will collaborate with the CQE on student opportunities and research.
Many of the new industry partners already have ongoing or recent engagements with CQE and its member institutions. In recent collaborative research, spectrally entangled photons from a Qubitekk entangled photon source were transported and successfully detected after traveling through one section of the Argonne quantum loop.
Another example of these relationships is the work that University of Chicago computer scientist Fred Chong and his students have done with both Intel and Rigetti Computing on software and hardware solutions. With Intel’s support, Chong’s team invented a range of software techniques to more efficiently execute quantum programs on a coming crop of quantum hardware. For example, they developed methods that take advantage of the hierarchical structure of important quantum circuits that are critical to the future of reliable quantum computation.
Jim Clarke, director of quantum hardware at Intel, looks forward to further collaborations with Chicago Quantum Exchange members.
“Intel remains committed to solving intractable challenges that lie on the path of achieving quantum practicality,” said Clarke. “We’re focusing our research on new qubit technologies and addressing key bottlenecks in their control and connectivity as quantum systems get larger. Our collaborations with members of the Chicago Quantum Exchange will help us harness our collective areas of expertise to contribute to meaningful advances in these areas.”
The Chicago Quantum Exchange’s partnership with JPMorgan Chase will enable the use of quantum computing algorithms and software for secure transactions and high-speed trading.
“We are excited about the transformative impact that quantum computing can have on our industry,” said Marco Pistoia, managing director, head of applied research and engineering at JPMorgan Chase. “Collaborating with the Chicago Quantum Exchange will help us to be among the first to develop cutting-edge quantum algorithms for financial use cases, and experiment with the power of quantum computers on relevant problems, such as portfolio optimization and option pricing.”
Applying quantum science and technology discoveries to areas such as finance, computing and healthcare requires a robust workforce of scientists and engineers. The Chicago Quantum Exchange integrates universities, national laboratories and leading companies to train the next generation of scientists and engineers and to equip those already in the workforce to transition to quantum careers.
“Microsoft is excited to partner with the Chicago Quantum Exchange to accelerate the advancement of quantum computing,” said Chetan Nayak, general manager of Microsoft Quantum Hardware. “It is through these academic and industry partnerships that we’ll be able to scale innovation and develop a workforce ready to harness the incredible impact of this technology.”