A university-industry collaboration has successfully run a quantum algorithm on a type of quantum computer known as a cold atom quantum computer for the first time. The achievement by the team of scientists from the University of Wisconsin–Madison, ColdQuanta and Riverlane brings quantum computing one step closer to being used in real-world applications. The work out of Mark Saffman’s group was published in Nature on April 20.
This story was originally published by the Chicago Quantum Exchange
The Open Quantum Initiative (OQI), a working group of students, researchers, educators, and leaders across the Chicago Quantum Exchange (CQE), announced the launch of the OQI Undergraduate Fellowship as part of their effort to advocate for and contribute to the development of a diverse and inclusive quantum workforce.
The primary mission of the OQI is to champion the development of a more inclusive quantum community. Science, technology, engineering, and mathematics (STEM) fields remain overwhelmingly white and male—only about 20% of bachelor’s degrees in physics, engineering, and computer science go to women, a mere 6% of all STEM bachelor’s degrees are awarded to African American students, and 12% of all STEM bachelor’s degrees are awarded to Hispanic students. But as the field of quantum science is still relatively new compared to other STEM subjects, groups like the OQI see a chance to make the foundations of the field diverse and accessible to all from the start.
“In many respects, we are building a national workforce from the ground up,” says David Awschalom, the Liew Family Professor in Molecular Engineering and Physics at the University of Chicago, senior scientist at Argonne National Laboratory, director of the Chicago Quantum Exchange, and director of Q-NEXT, a Department of Energy quantum information science center led by Argonne. “There are incredible opportunities here to make the field of quantum engineering as inclusive and equitable as possible from the very beginning, creating a strong ecosystem for the future.”
At the heart of the OQI’s effort is a new fellowship starting in summer 2022. For 10 weeks, fellows will live and work at a CQE member or partner institution, completing a research project in quantum information science and engineering under the guidance of a mentor. Students will have numerous opportunities to interact with the other fellows in their cohort during the summer research period and throughout the following academic year.
Through this fellowship, the students can expand their understanding of quantum science, receive career guidance, and grow their professional networks with leaders in academia and industry. The OQI will also aim to provide future research experiences in subsequent summers, as well as provide opportunities to mentor future fellows, helping to build a larger, diverse quantum community over time.
With the support of CQE’s member and partner institutions, including the University of Chicago, Argonne, Fermilab, University of Illinois Urbana-Champaign, University of Wisconsin-Madison, Northwestern University, and The Ohio State University, along with the NSF Quantum Leap Challenge Institute for Hybrid Quantum Architectures and Networks (HQAN) and Q-NEXT, this fellowship helps to establish diversity, equity, and inclusion as priorities central to the development of the quantum ecosystem.
The OQI launched the fellowship alongside a workshop on September 22 and 23. The OQI workshop, titled “Building a Diverse Quantum Ecosystem,” brought together CQE students, researchers, and professionals from across different institutions, including industry, to discuss the prevailing issues and barriers in quantum information science as the field develops. Institutional changemakers also shared what they have learned from their own efforts to increase representation. A panel on education and workforce development at the upcoming Chicago Quantum Summit on Nov. 4 will continue the discussion on building inclusive onramps for the quantum information science field.
“For quantum science and engineering to achieve its full potential, it must be accessible to all,” says Kayla Lee, Academic Alliance Lead at IBM Quantum and keynote speaker of the OQI workshop. “The OQI Undergraduate Fellowship provides explicit support for historically marginalized communities, which is crucial to increasing quantum engagement in a way that creates a more diverse and equitable field.”
Applications for the OQI Undergraduate Fellowship are open now.
Small but mighty, semiconducting qubits are a promising area of research on the road to a fully functional quantum computer. Less than one square micron, thousands of these qubits could fit into the space taken up by one of the current industry-leading superconducting qubit platforms, such as IBM’s or Google’s.
For a quantum computer on the order of tens or hundreds of qubits, that size difference is insignificant. But to get to the millions or billions of qubits needed to use these computers to model quantum physical processes or fold a protein in a matter of minutes, the tiny size of the semiconducting qubits could become a huge advantage.
Except, says Nathan Holman, who graduated from UW–Madison physics professor Mark Eriksson’s group with a PhD in 2020 and is now a scientist with HRL Laboratories, “All those qubits need to be wired up. But the qubits are so small, so how do we get the lines in there?”
In a new study published in NPJ Quantum Information on September 9, Holman and colleagues applied flip chip bonding to 3D integrate superconducting resonators with semiconducting qubits for the first time, freeing up space for the control wires in the process. They then showed that the new chip performs as well as non-integrated ones, meaning that they solved one problem without introducing another.
If quantum computers are to have any chance of outperforming their classical counterparts, their individual qubit units need to be scalable so that millions of qubits can work together. They also need an error correction scheme such as the surface code, which requires a 2D qubit grid and is the current best-proposed scheme.
To attain any 2D tiled structure with current semiconducting devices, it quickly gets to the point where 100% of available surface area is covered by wires — and at that point, it is physically impossible to expand the device’s capacity by adding more qubits.
To try to alleviate the space issue, the researchers applied a 3D integration method developed by their colleagues at MIT. Essentially, the process takes two silicon dies, attaches pillars of the soft metal indium placed onto one, aligns the two dies, and then presses them together. The result is that the wires come in from the top instead of from the side.
“The 3D integration helps you get some of the wiring in in a denser way than you could with the traditional method,” Holman says. “This particular approach has never been done with semiconductor qubits, and I think the big reason why it hadn’t is that it’s just a huge fabrication challenge.”
In the second part of their study, the researchers needed to confirm that their new design was functional — and that it didn’t add disadvantages that would negate the spacing success.
The device itself has a cavity with a well-defined resonant frequency, which means that when they probe it with microwave photons at that frequency, the photons transmit through the cavity and are registered by a detector. The qubit itself is coupled to the cavity, which allows the researchers to determine if it is functioning or not: a functioning qubit changes the resonant frequency, and the number of photons detected goes down.
They probed their 3D integrated devices with the microwave photons, and when they expected their qubits to be working, they saw the expected signal. In other words, the new design did not negatively affect device performance.
“Even though there’s all this added complexity, the devices didn’t perform any worse than devices that are easier to make,” Holman says. “I think this work makes it conceivable to go to the next step with this technology, whereas before it was very tricky to imagine past a certain number of qubits.”
Holman emphasizes that this work does not solve all the design and functionality issues currently hampering the success of fully functional quantum computers.
“Even with all the resources and large industry teams working on this problem, it is non-trivial,” Holman says. “It’s exciting, but it’s a long-haul excitement. This work is one more piece of the puzzle.”
The article reports that this work was sponsored in part by the Army Research Office (ARO) under Grant Number W911NF-17-1-0274 (at UW–Madison) and by the Assistant Secretary of Defense for Research & Engineering under Air Force Contract No. FA8721-05-C-0002 (at MIT Lincoln Laboratory).
Quantum computers could outperform classical computers at many tasks, but only if the errors that are an inevitable part of computational tasks are isolated rather than widespread events.
Now, researchers at the University of Wisconsin–Madison have found evidence that errors are correlated across an entire superconducting quantum computing chip — highlighting a problem that must be acknowledged and addressed in the quest for fault-tolerant quantum computers.
The researchers report their findings in a study published June 16 in the journal Nature, Importantly, their work also points to mitigation strategies.
“I think people have been approaching the problem of error correction in an overly optimistic way, blindly making the assumption that errors are not correlated,” says UW–Madison physics Professor Robert McDermott, senior author of the study. “Our experiments show absolutely that errors are correlated, but as we identify problems and develop a deep physical understanding, we’re going to find ways to work around them.”
Read the full story at https://news.wisc.edu/correlated-errors-in-quantum-computers-emphasize-need-for-design-changes/
With the best of wishes — and some sadness — the Department of Physics says “Happy Retirement” to Professor Sue Coppersmith. Her last day at UW–Madison was February 14.
Coppersmith, the Robert E. Fassnacht Professor of Physics, joined the department in 2001. Prior to coming to UW–Madison, she earned her Ph.D. from Cornell University, conducting her thesis work at Bell Labs. She completed a postdoc at Brookhaven National Lab, then worked at Bell Labs for eight years before joining the faculty at the University of Chicago.
During her tenure here, she served as Department Chair for one three-year term, and earned recognition as a Fellow of the National Academy of Sciences, the American Academy of Arts and Sciences, the American Association for the Advancement of Science, and the American Physical Society.
Scientific Achievements
At UChicago, Coppersmith’s research focused on soft matter physics and non-linear dynamics, work that she continued at UW–Madison, primarily with Prof. Pupa Gilbert. But her research program largely shifted over the years into quantum computing, an area that was just getting started when she started in Madison..
“At the time, I would tell people what we were doing, and of course nothing was working yet, and people would say, ‘Well, that’s all crap, isn’t it?’” Coppersmith recalls. “So, it was really fun to go from a time where there was nothing working, to now we have qubits, and being a part of the effort and feeling like I was helping.”
Coppersmith describes herself as a theorist who went into the lab every day to better understand the experimental side of quantum computing, And, she says, UW–Madison stands out as one of the universities where theory and experiment are so closely tied together. Here, she frequently collaborated with Prof. Mark Eriksson and Distinguished Scientist Mark Friesen.
“She just comes up with a lot of ideas, and what matters most is how many of them are home runs. She had an unusually large number,” Eriksson says. “She came up with the idea for a brand new qubit, the quantum dot hybrid qubit, and we’re still working on it to this day in my lab. And other people around the world have picked it up.”
Friesen adds:
“As a researcher, Sue is highly intuitive and focused more on the high-level physical picture rather than specific technical details. She typically breaks a problem down to a ‘minimal model’ that captures its basic physics. She has studied a wide variety of problems in her career, for which she is highly respected in many different communities, and she is able to apply lessons learned from one area to another. Her memory is legendary! She is also known for her quickness, both in being able to understand a problem (and how it fits into the big picture) and being able to immediately respond to it. I also say this in a good way: she is not shy about expressing her opinions.”
Legacy as Department Chair
Perhaps equal to her scientific achievements is the mark Coppersmith made on the department during her time as Chair, from 2005-08. The Department was hiring three faculty positions, and she reasoned that if eight offers were made, at worst four people would accept.
“But eight people came! And I was famous for it because I ruined the College’s budget,” Coppersmith says. “I think this is the highlight of my Chair career. I loved recruiting people.”
There are a number of factors that go into faculty candidates accepting or not accepting offers, but Eriksson is certain that Coppersmith‘s ability to recruit was a significant one.
“They came in large part because Sue understood and was able to get them to explain and she was able to hear what they really needed, and then go deliver on it,” Eriksson says. “It’s one thing to have any subset of those skills, but she has the whole package.”
Current Department Chair Sridhara Dasu credits Coppersmith with shaping the direction of the department in all areas of physics, adding, “Her tenure continues to be an inspiration for all chairs of the department who followed her.”
Mentorship of students and colleagues
Coppersmith’s mentorship of junior colleagues and students will also be missed. Both Friesen and Susan Nossal, senior scientist and director of the Physics Learning Center, noted that Coppersmith’s support has been crucial to their success as researchers in the department. They both applauded her as a champion of women and girls in science, citing her participation – with Nossal, Gilbert and several graduate students – in the annual Expanding Your Horizons event at which middle school girls participate in fun, hands-on science activities.
“As a mentor, she is highly dedicated to her students and colleagues,” says Friesen, who co-advised several students with Coppersmith. “For me personally, she has been very supportive of my career path, helping me to obtain promotions and advancements, and providing on-point advice.”
Adds Nossal: “As a scientist, you have your ups and downs, and she helped me through some of the downs. It’s always helpful to have people who believe in you, and she helped me in persisting as a scientist.”
Looking forward
Between Coppersmith and everyone else mentioned in this piece, there were certainly plenty of stories that could be shared. But for now, we’ll let emeritus professor Lou Bruch sum up Coppersmith’s tenacity and well-placed ambition with this anecdote:
“Sue touted the usefulness of the Mathematica package and would at times get into competition on speed of getting to the answer — her using the package and me using ad hoc analyses. I recall only one instance where I won.”
Coppersmith may be retired from UW–Madison, but she is not retiring from science. She is currently Professor and Head of the School of Physics at the University of New South Wales in Australia, where she will continue her research and collaborations with colleagues here and around the world.
“Wisconsin was so good to me. The people are so nice, and we did good work,” Coppersmith says. “I like to feel that I contributed in a positive way. I’ll always be grateful.”
University of Wisconsin–Madison physics professor Victor Brar has been named a 2021 Sloan Research Fellow, a competitive award given to researchers in the early stages of their careers.
“A Sloan Research Fellow is a rising star, plain and simple,” says Adam F. Falk, president of the Alfred P. Sloan Foundation. “To receive a Fellowship is to be told by the scientific community that your achievements as a young scholar are already driving the research frontier.”
Brar’s research focuses on developing new microscopy techniques to look at quantum systems in ways that current microscopes cannot. Applying these techniques to study defects in materials — where a perfect crystal lattice is disrupted by one or more anomalous atoms — could lead to improvements in quantum computer performance or the discovery of new Physics.
“Everyone in the world is trying to make a quantum computer, but we don’t really have good diagnostics for what all the quantum systems are inside of a material,” Brar says. “One goal with this microscope is to figure out what’s in a material that could interfere with a quantum computer.”
Additionally, Brar hopes that by applying this technique to complex materials, new particles may be identified and studied. For example, many particle physics discoveries, such as the Higgs boson and the positron, have been first theorized based on materials science research and repurposed into high energy physics experiments.
“At CERN, for example, they try to get to higher and higher energies to see particles, and at some point CERN just can’t get high enough,” Brar explains. “But in a material, you can get analogous particles for what CERN scientists are looking for but at much lower energies. There are particles that we’ve never seen outside of a material, but we can see them in a material, and those are the kinds of things that we’d ideally like to study.”
The technique that Brar is developing combines optical and electron microscopy, two methods he worked on as a graduate student and post-doc. By bringing them together now, he hopes that his unique method will bring significant advances to his field — and that the Sloan Fellowship indicates that other scientists agree.
“The Sloan award has a history behind it, and they have a track record of funding good science,” Brar says. “So, it means a lot to be recognized by Sloan and I hope it will help when we start to try to make our case for why this method is important.”
The Sloan Research Fellowship is open to early-career scientists in one of eight fields, including physics. More than 1000 researchers are nominated each year for 128 fellowship slots. Winners receive a two-year, $75,000 fellowship which can be spent to advance the fellow’s research.
“Prof. Victor Brar winning the Sloan Foundation Fellowship is a very welcome recognition,” says Sridhara Dasu, chair of the UW–Madison physics department. “For decades now, the Sloan Fellowship is a highly sought-after honor amongst young scientists, and it is wonderful to note that our enthusiasm and confidence in Prof. Brar’s research prowess is recognized by an international panel selecting the Sloan Fellows.”