Fred Chong, the Seymour Goodman Professor in the Department of Computer Science, was elevated to IEEE Fellow in the organization’s 2023 class. The distinction was given to Chong for “contributions to the field of quantum computer architecture, compilation and optimization.”
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Franklin Named ACM Distinguished Member
Diana Franklin, associate professor of computer science and leading researcher on inclusive K-12 computer science education, was named a Distinguished Member by the Association for Computing Machinery (ACM), the world’s largest computing society.
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In-Fridge Controller Could Scale Up Quantum Computers, Award-Winning EPiQC Research Finds
A new approach from computer scientists and physicists at the University of Chicago, presented at QCE 2021, can help overcome major scalability obstacles standing in the way of larger-scale quantum computers.
A collaboration between computer scientists and physicists at the University of Chicago broke through one of the key obstacles for large-scale quantum computing by figuring out how to move their control signals “inside the fridge.”
Current quantum chips must be stored at extremely cold temperatures inside a dilution refrigerator, but are controlled by signals from a classical controller at room temperature. The costs and hardware required for this setup limits the scalability of the technology, which will be necessary to capture this new technology’s enormous potential for cryptography, molecular simulation, and other applications.
The UChicago research team demonstrated low-error two-qubit operations using Superconducting Single Flux Quantum (SFQ) pulses, which are voltage signals generated inside the fridge. The finding is an essential step to realize universal quantum computing at large scales.
The interdisciplinary research was conducted as a part of the Enabling Practical-scale Quantum Computation (EPiQC) project, an NSF Expedition in Computing. The research was recently published in the 2021 IEEE International Conference on Quantum Computing and Engineering (QCE), where it received a Best Paper Award. The authors of this paper are Mohammad Reza Jokar, Richard Rines, and Frederic Chong.
Towards large-scale quantum machines
Superconducting quantum computing is one of the leading technologies to realize quantum computers. Small quantum computer prototypes based on this technology with up to around 100 qubits have been manufactured in recent years thanks to efforts in industry and academia. The quantum chip in these prototypes is located inside a dilution refrigerator at millikelvin temperature, and quantum operations are performed by sending microwave control signals for each qubit from a classical controller at room temperature. Unfortunately, this control approach has severe scalability challenges due to the massive energy costs of generating the microwave signals at room temperature and routing them to the quantum chip using coaxial cables.
To address these scalability challenges, one solution proposed in the literature is to generate and route the control signals locally inside the quantum fridge. SFQ is a classical logic technology that can operate inside the quantum fridge with very low power consumption, thus enabling an in-fridge controller with maximized scalability. Prior work used a genetic algorithm to find SFQ pulse trains that implement single-qubit operations with low error using SFQ pulses. However, little research has been done on SFQ-based two-qubit operations, which are essential to realize universal quantum computing.
SFQ-based two-qubit operations with low error
UChicago researchers found it challenging to realize SFQ-based two-qubit gates due to high leakage to non-computational subspace of the qubits. Here, the computational subspace includes the first two energy levels of the qubit, and leakage is the probability of measuring the qubit in a higher energy level at the end of the gate.
“However, realizing low-leakage SFQ-based two-qubit gates is possible by carefully engineering the quantum system and optimizing both software and hardware,” said Mohammad Reza Jokar, a Ph.D. candidate at the University of Chicago and co-author of the QCE paper.
Prior work on SFQ-based single-qubit operations focused on minimizing the leakage at the end of the quantum gate, which leads to low-leakage gates. However, this strategy does not work well for SFQ-based two-qubit operations. UChicago researchers found that without active suppression of the leakage during the execution of the SFQ-based two-qubit operations, leakage occurs that will not be captured by their model.
Thus, at the software level, researchers modified existing quantum optimal control methods to actively suppress the leakage during the quantum gate by modeling one extra energy level and penalizing the leakage to that energy level after applying each SFQ pulse. In addition, they expanded the solution space and accepted solutions that are accurate up to single-qubit rotations around the Z axis; such solutions are acceptable because Z rotations can often be commuted through subsequent operations or implemented virtually. By expanding the solution space, they were able to find SFQ pulse trains with lower leakage.
At the hardware level, the researchers examined different qubit architectures for their potential advantages. In addition to transmon, which is a widely used qubit, they studied fluxonium, which has high anharmonicity and is designed to naturally suppress leakage. They also studied the impact of using inductive coupling instead of capacitive coupling, and showed that it can help realize two-qubit gates with low leakage and short quantum gate time. Finally, they studied the impact of tip angle, a parameter that determines the amount of energy deposited per each SFQ pulse. Smaller tip angle allowed for more fine-tuned control of the SFQ pulse trains which helped realize better quantum gates with lower leakage.
The results presented in the paper show that it is possible to realize SFQ-based two-qubit gates with gate error and gate time similar to microwave-based gates, after carefully engineering an SFQ-friendly quantum system. These results indicate that SFQ is a promising approach for quantum control as it can deliver scalability as well as low-error quantum operations.
“In this paper, we study the practical implications of realizing SFQ-based two-qubit gates,” said Jokar. “One key next step is to design an in-fridge controller architecture as well in order to have a complete controller system.”
Super.tech/EPiQC Research Informs New Suite of Benchmarks for Quantum Computers - HPCA Best Paper Award Winner
Super.tech, a quantum computing startup co-founded by UChicago CS Professor Fred Chong and PhD alumnus Pranav Gokhale, announced the release of SupermarQ, a new, application-centric benchmarking suite for quantum computers. The product builds on research conducted with the Enabling Practical-scale Quantum Computing (EPiQC) collaboration, an NSF Expedition in Computing led by Chong, the Seymour Goodman Professor in the Department of Computer Science. SupermarQ bench marking suite receives HPCA Best Paper Award.
Benchmarking is a keystone of the computing industry and is especially important for quantum computing at this stage of development. SupermarQ is a suite of benchmarks that measure a machine’s performance on a range of applications. These applications mirror real-world problems in a variety of domains such as finance, chemistry, energy, and encryption.
“Effective benchmarks can accelerate progress across the entire quantum ecosystem by stimulating investment in the right areas,” said Matt Langione, a partner and leader of the Deep Tech practice at BCG who specializes in quantum computing. Moreover, quantifying progress towards functional quantum computers is a matter of national security, as evidenced by DARPA’s recent solicitation of a Quantum Benchmarking program in mid-2021.
Many current benchmarks measure single operations or attempt to combine many aspects of performance into a single number. These approaches result in metrics which can end up comparing apples to oranges or lack a clear connection to commercial viability.
SupermarQ stands out in that it is motivated by real-world use cases –assessing how well a device can complete a given task, such as optimization, simulation, or error correction. Problem-solving with quantum computers requires different configurations depending on the problem, making some machines better at certain tasks than others. In this way, SupermarQ highlights the diversity of quantum computing architectures that exist today.
“We believe SupermarQ can become the go-to resource for quantum customers when deciding which device to use,” said Pranav Gokhale, Super.tech’s co-founder and CEO. “Our approach illustrates the importance of matching the device architecture to the use-case.”
Langione lends support to the Super.tech approach, stating “Application benchmarks are among the best tools to help companies determine which devices best meet their quantum computing needs.” Read more about the quantum benchmarking landscape in BCG’s latest white paper, here.
Another key attribute of SupermarQ is its scalability. The benchmarks use “cunning” mathematical designs, results of which will be verifiable even when quantum outpaces traditional computers. This cannot be said for other approaches, whose evaluation will become intractable when the inevitability of quantum supremacy is reached.
This benchmarking work is based on an academic paper authored by Super.tech employees and members of EPiQC. SupermarQ: A Scalable Quantum Benchmark Suite will appear in the IEEE HPCA 2022 conference.
Super.tech encourages readers to check out their web portal, where it is free to toggle between SupermarQ benchmark results and download materials for further exploration. For those interested in computing their own benchmarks, the SupermarQ codebase is open-sourced and can be run by anyone.
SupermarQ stands out from existing quantum benchmarking techniques. Chong, Super.tech’s co-founder and Chief Scientist, asserts, “We hope to drive a new way of thinking about quantum evaluation, one that’s based on capabilities, as quantum begins to be integrated into real-world workflows.”
Super.tech would like to thank P33 for their support in bringing this initiative to life.
EPiQC Research Receives Best Paper Award at IEEE Quantum Week
A new strategy developed by EPiQC researchers to expand the scalability of quantum computers received a Best Paper Award at the 2021 IEEE International Conference on Quantum Computing and Engineering, also known as IEEE Quantum Week.
EPiQC Alum Yongshan Ding Joins Yale CS Faculty
Ding, who worked in Chong’s research group as part of the Enabling Practical-Scale Quantum Computing (EPiQC) collaboration, is the first quantum computing specialist hired by Yale’s CS department.
Three EPiQC Papers Chosen By IEEE Micro for Annual Top Picks Awards
EPiQC Lands Two IEEE Micro 2019 Top Picks
Each year, the IEEE Micro journal selects a dozen papers from major computer architecture conferences that represent the “best of the best” in the field. These papers are “recognized for their importance, mainly the long-term impact and influence on the industry and other researchers,” writes the journal in their May/June issue.
This year, both of the Top Picks selections on quantum computing came from the Enabling Practical-Scale Quantum Computing (EPiQC) collaboration . The papers by EPiQC-affiliated authors from UChicago, Princeton, and Duke explored the use of three-level qutrits for quantum computing and evaluated the architectural design of today’s quantum computers.
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Franklin Lead Writer of "Key Concepts for Future QIS Learners"
If quantum information science will drive the most powerful technology of the near future, it’s important to start training tomorrow’s quantum workforce today. To set the guideposts for how that education can start before college, the National Science Foundation and the White House Office of Science and Technology Policy recently convened a group of educators, researchers, and industry representatives for a virtual "Key Concepts for Future Quantum Information Science Learners” workshop.
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image credit (Bill Pietsch, Astronaut 3 Media)
EPiQC Students Soar
Congratulations to Prakash Murali (Princeton), Lia Yeh (UCSB), Emma Dasgupta (UChicago) and Thomas Propson (UChicago)!
Graduate student Prakash Murali (Princeton) was awarded a prestigious 2020 IBM PhD fellowship. For 70 years IBM has recognized and rewarded outstanding PhD students around the world through a highly competitive PhD Fellowship Award program. The distinguished 2020 IBM PhD Fellowship Award Program is an intensely competitive worldwide program, which recognizes and supports exceptional PhD students who want to make their mark in promising and disruptive technologies. His advisor Margaret Martonosi, H. T. Adams ‘35 Professor of Computer Science at Princeton University, explained why the fellowship was well deserved. “This is for his outstanding work on toolflows and architectural issues for quantum computing systems. In addition to an impressive set of outstanding papers in general, he’s also had a very successful long-term collaboration with IBM, including a stint there last summer that led to his recent ASPLOS paper”
EPiQC undergraduates have also received a slew of recognition. Thomas Propson (UChicago) who has worked on both QC architecture and hardware with Fred Chong and David Schuster was awarded a Barry Goldwater Scholarship based on academic merit in the natural sciences, mathematics and engineering. “If I had to summarize my current career goal in a sentence: I want to create technology that improves the quality of people’s lives,” he said. (see UChicago story)
Lia Yeh, a UCSB undergraduate who worked with EPIQC team members at Princeton during the Summer, 2019 Princeton-IBM QURIP program, has received several honors. First, Lia received a Clarendon Award fellowship to attend Oxford University that includes a full scholarship for her PhD studies in quantum computing. Second, Lia has been named a recipient of the prestigious US National Science Foundation (NSF) Graduate Research Fellowship. Third, Lia along with Emma Dasgupta (UChicago) brought home the undergraduate gold and bronze medals in the ACM Student Research Competition at the MICRO52 Symposium. Both of these medals pertained to EPIQC-related QURIP projects that Lia and Emma performed at Princeton and IBM in Summer 2019. The ACM Student Research Competition (SRC), sponsored by Microsoft, offers a unique forum for undergraduate and graduate students to present their original research at well-known ACM sponsored and co-sponsored conferences before a panel of judges and attendees. Emma who also worked with Margaret Martonosi won third place for her poster “Statistical Assertions for Debugging in Qiskit”. During the academic year, she works in the Chong group.
As first place winner in the SIGMICRO level of the competition, Lia advanced to the AMC Grand Finals for her work on “Benchmarking ZX-Calculus Circuit Optimization Against Qiskit Transpilation”.
Bravo!
IBM Q Best Paper Award for VQE Research
First prize in the 2019 IBM Q Best Paper Award competition was awarded to graduate student Pranav Gokhale and fellow EPiQC researchers for work on increasing the efficiency of key quantum algorithms. The paper, “Minimizing State Preparations in Variational Quantum Eigensolver (VQE) by Partitioning into Commuting Families,” examined how to reduce measurements, one of the biggest overhead costs in VQE. VQE is a “killer app” for near-term quantum computing, primarily for finding the ground state energy of a molecule, an important and computationally difficult calculation, which consumes a significant fractions of world’s supercomputing resources. (Watch - Gokhale explain their research in this short video. )
With their approach, the authors reduced the computational cost of running the VQE algorithm by 7-12 times. They experimentally validated the approach on one of IBM’s cloud-service 20-qubit quantum computers. The authors have shared their Python and Qiskit code for generating circuits for simultaneous measurement. For more on the research and the IBM Q Best Paper Award, see the IBM Research Blog, as well as coverage by the Uchicago CS Department
How K–12 Education Fits into the Future of Quantum Computing
EPiQC PIs Diana Franklin and Ken Brown quoted in:
How K–12 Education Fits into the Future of Quantum Computing
EPiQC Student Named 2019 Siebel Scholar
EPiQC to help lead effort to build first practical quantum computer
Quantum Computing Tutorials
EPiQC has presented a series of tutorials to introduce the computer science community and others to quantum computing. The EPiQC team presented tutorials at: MICRO 51, the Argonne Training Program on Extreme-Scale Computing (ATPESC), the Ontario Science Center, and ISCA 2018. The 2018 ISCA tutorial: Grand Challenges and Research Tools for Quantum Computing videos and slides are available below.
Intro and Research Challenges (Fred Chong)
Tools for QC Arch Research (Margaret Martonosi)
Quantum Basics and Algorithm Demo (Ali Javadi-Abhari)
Quantum Approximate Optimization Algorithms (Peter Shor)
Quantum Chemistry Algorithms (Ken Brown)
Variational Quantum Eigensolver Demo (Pranav Gokhale)
Diana Franklin Testifies before Congress
Diana Franklin testified on Capitol Hill for the "Disrupter Series: Quantum Computing" hearing of the One Hundred Fifteenth Congress of the United States. Franklin emphasized the importance of workforce development, described key educational initiatives of EPiQC which range from tutorials for CS faculty to K-12 curriculum, and highlighted the importance of funding continuity to maintain competitiveness.
Written testimony as well as the video of oral testimony and responses to panel members questions from Franklin and the other distinguished witnesses can be seen on this C-SPAN video
Related Coverage:
UChicago Computer Science Department News
Yunong Shi Awarded NSF QISE-NET Fellowship
Yunong Shi's collaborative research program will develop software to optimize quantum compliation for near-term quantum machines and will be jointly supervised by Andrew Cross (IBM) and Fred Chong (UChicago) . The project is a "Triplet" within the NSF Quantum Leap Big Idea umbrella. Each triplet is comprised of a three-person team which includes a university faculty member, an industrial researcher, and a graduate student serving as the pivotal component of the group. Three-year QISE-NET awards are specifically designed to bridge the the second quantum revolution's workforce development gap, and to increase academia-industry interactions.
Yunong Shi's work will be a key mechanism to make quantum algorithms run more efficiently on realistic machines. In addition to thesis development this award will enable extended visits to IBM, and network – level mentoring opportunities. QISE-NET awards are only made to projects that represent exciting, leading-edge, trail-blazing research topics in Quantum Information Science (QISE) that exhibit the potential for growth and follow-on work between the student, company and academic groups, and which demonstrate strong alignment between the activities of the academic group and the industrial group.
EPiQC Lead Fred Chong's ASPLOS 2018 Keynote Explored the Grand Challenges of Practical Quantum Computing for Computer Scientists
Chong's keynote talk, “Quantum Computing is Getting Real: Architecture, PL, and OS roles in Closing the Gap between Quantum Algorithms and Machines,” was presented at the ASPLOS 2018 Meeting . ASPLOS (ACM International Conference on Architectural Support for Programming Languages and Operating Systems) is "the premier forum for multidisciplinary systems research spanning computer architecture and hardware, programming languages and compilers, operating systems and networking." Chong's talk highlighted the unique time this is for the field of quantum computing, the potential transformative power of 100-1,000 qubit machines that are coming on-line in the next few years, and the key role that the computer science community must play in closing the gap between practical quantum algorithms and these real machines.
Chong discussed how these near-term machines may "fundamentally change our concept of what is computable," and outlined specific opportunities/challenges involved in vertically integrating software and hardware in the upcoming era of noisy intermediate-scale quantum (NISQ) technology. (see ASPLOS conference summary).
ASPLOS 2018 PROGRAM LISTING:
Keynote: Fred Chong, Seymour Goodman Professor of Computer Architecture,
University of Chicago
Title: “Quantum Computing is Getting Real: Architecture, PL, and OS roles in Closing the Gap between Quantum Algorithms and Machines”
Abstract: Quantum computing is at an inflection point, where 50-qubit (quantum bit) machines have been built, 100-qubit machines are just around the corner, and even 1000-qubit machines are perhaps only a few years away. These machines have the potential to fundamentally change our concept of what is computable and demonstrate practical applications in areas such as quantum chemistry, optimization, and quantum simulation.
Yet a significant resource gap remains between practical quantum algorithms and real machines. There is an urgent shortage of the necessary computer scientists to work on software and architectures to close this gap.
I will outline several grand research challenges in closing this gap, including programming language design, software and hardware verification, defining and perforating abstraction boundaries, cross-layer optimization, managing parallelism and communication, mapping and scheduling computations, reducing control complexity, machine-specific optimizations, learning error patterns, and many more. I will also describe the resources and infrastructure available for starting research in quantum computing and for tackling these challenges.
"What is the role of Architecture and Software Researchers on the Road to Quantum Supremacy?"
Margaret Martonosi keynote at HPCA-24 in Vienna, Austria
EPiQC Co-PI Margaret Martonosi gave the Keynote lecture at the 24th IEEE International Symposium on High-Performance Computer Architecture (HPCA-24) . HPCA is the the premier international forum for presenting research results in high performance and parallel computing. Martonosi’s keynote talk entitled “What is the role of Architecture and Software Researchers on the Road to Quantum Supremacy?” explored fundamental themes of the EPiQC NSF Expedition project including the promises and challenges of near-to-intermediate term quantum computing.
Martonosi discussed the role of systems researchers in helping realize the promise of quantum computing. She also described important tools that need to be developed to make quantum computing practical in the near term such as: high-level programming languages, compilers, error correcting codes (ECC), control software, debugging tools, and hybrid, application-aware, ECC mechanisms. Additionally Martonosi was awarded the inaugural HPCA Test of Time Award with David Brooks for their paper, “Dynamically exploiting narrow width operands to improve processor power and performance”, HPCA ’99.
KEYNOTE ABSTRACT
Martonosi’s Keynote was highlighted in the ACM SIGARCH - HPCA-24 CONFERENCE SUMMARY
