Condensed matter

Welcome, Prof. Britton Plourde!

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Britton Plourde (credit: Isabelle Delfosse, L&S)

Condensed matter experimentalist Britton Plourde received his bachelor’s in physics and music performance from the University of Michigan. He then went to grad school at UIUC, earning a PhD in physics and a master’s in music performance. He completed a postdoc at UC-Berkeley, then began as an assistant professor of physics at Syracuse University in 2005, moving up the ranks to full professor there. In Fall 2024, Plourde joined the UW–Madison physics department as a full professor. He is joining the department on a half-time appointment; for the other half, he will be working at Qolab, a quantum computing startup company based in Madison.

 Please give an overview of your research.

I work on superconducting quantum circuits. We make microfabricated superconducting circuits that have what are called Josephson tunnel junctions in them. And one of the biggest things we use these for is making qubits. We study all of the various physics related to how qubits work, what limits their performance, and ways to make them perform better so you could eventually build a practical, large-scale quantum computer. My research is similar to Robert McDermott’s and Roman Kuzmin’s.

What are the first one or two projects that you will have your group working on or continuing to work on when you arrive in Madison?

The company I’m working with, Qolab, is focused on building a quantum computer. My academic research lab at the university will be focused on fundamental physics related to operation of qubits, including the individual components of qubits like the Josephson junctions and to different processes that limit the performance of qubits. At the same time, the company is really focused on the technology of fabricating lots of qubits in a uniform, reproducible way and building them into a quantum computer.

In my group, a significant focus is going to be on understanding quasiparticles in superconducting qubits and how they impact the behavior of those qubits. Quasiparticles are electronic excitations above the superconducting ground state. The superconducting ground state is important because it doesn’t have any dissipation. But these quasiparticles are dissipative, and they can degrade the performance of a superconducting circuit. There are various things that can generate the quasiparticles, but one of them is radioactivity: background radiation from radioactive contaminants in the lab or from cosmic rays. My group is going to continue spending time on understanding the physics of those processes and coming up with ways to try to mitigate their effects to make qubits that are more immune to quasiparticles.

We’re also hoping to study quasiparticle physics in qubits for the completely opposite reason: instead of trying to mitigate the effects of quasiparticles to make better qubits, it’s to amplify the effects of quasiparticles to make better detectors, potentially to detect dark matter particles. Robert and I are co-principal investigators with some particle physics collaborators on two Department of Energy proposals for this work that we recently submitted. This work hasn’t been funded yet, but if it is, it is going to be a new and interesting research direction in both of our groups.

What attracted you to Madison and the university?

It’s a great department. I’ve known it for a long time because I collaborated with Robert almost as long as he’s been there. I’ve visited a lot over the years, and I like the area and the city. The university has made an impressive investment in quantum information science, and they’re a real leader in that area and have research strengths across multiple different qubit technologies, both experimentally and with a strong team of theorists working on different aspects of quantum information science and condensed matter. It’s really a powerhouse place, so I’m excited to join. University leadership has also been very supportive of the startup, they’re strongly encouraging of the entrepreneurial direction of faculty, and that’s not the case at a lot of other places.

What is your favorite element and/or elementary particle?

My favorite element has to be aluminum. That’s the superconductor we use the most. The same aluminum that you could use to wrap a hot dog at a baseball game to keep it warm, you can instead cool it down to below one degree Kelvin and it becomes a superconductor. And it makes great Josephson junctions for qubits.

What hobbies and interests do you have?

Well, I’m still a musician, I’m a flutist. I don’t really make money on it anymore, but I was a professional musician for a while. For the last three years of grad school, I had a job in a professional orchestra. I do still play occasionally, and I’ll have to see how much time I have when we get to Madison. My wife is a professional musician. She’s an oboist and she’ll be working part time in the School of Music developing a new monthly recital series.

Welcome, Professor Ben Woods!

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Ben Woods

Condensed matter theorist Ben Woods joined the department as an assistant professor this fall. Originally from a small town in North Dakota, Woods studied physics at the University of North Dakota and earned a PhD in physics from West Virginia University. He first came to UW–Madison for a postdoc with Mark Friesen in 2021, and now moves into his faculty role.

Please give an overview of your research.

I primarily work in two main areas of condensed matter theory and quantum information science. The first area is the theory of semiconductor quantum dots, with applications towards building and operating quantum computers based on spin qubits. Quantum dots can be thought of as artificial atoms in which electrons are trapped and manipulated within a semiconductor, such as silicon, by metallic gates that sit on top of the semiconductor. An electron in the quantum dot forms the basis for a type of qubit called a spin qubit, where the quantum information is stored in the spin of the electron. I investigate how we can build higher quality spin qubits. One aspect of this is analyzing and designing single and two qubit gates such that their efficiency and noise resiliency can be improved. Another aspect is studying the materials and design of quantum dot devices to optimize certain properties, such as how the qubits respond to an external magnetic field. I am also interested in quantum dot arrays as a platform for quantum simulation. Here the idea is to engineer the interactions between the quantum dots to emulate a quantum system of interest.

The other area I work in is semiconductor-superconductor heterostructures. Here, you’re trying to combine desirable properties of both types of materials to create interesting devices that would otherwise be impossible. I study semiconductor-superconductor heterostructures that can give rise to exotic particles known as Majorana zero modes, which form the basis for topological qubits. These qubits are immune to certain error sources that more conventional types of qubits are not. I am trying to understand the effects of disorder on these heterostructures and develop new schemes in which Majorana zero modes can be realized.

What are one or two of the main projects your group will work on first?

One initial project will focus on designing a new qubit architecture for quantum dot spin qubits. In the most conventional type of spin qubit, you have a single electron spin that is manipulated by jiggling it with an electric field back and forth within a single quantum dot. It turns out, however, that these qubits can be manipulated more efficiently if you can hop electrons between multiple quantum dots. Specifically, I’ve devised new schemes involving three dots in a triangular geometry in which single-qubit gates can be performed quite efficiently. These ideas work in principle, but now it’s a matter of quantitatively studying how noise resilient the scheme is and how finely tuned the system parameters need to be for things to go as planned.

A second initial project is more towards quantum simulation using quantum dot arrays. The project will focus on studying magnetism in quantum dot arrays. In other words, asking how the spins of the quantum dot electrons organize due to their mutual interaction. One interesting wrinkle in these quantum dot arrays based on silicon is that there is a valley degree of freedom in addition to the usual spin degree of freedom. The project involves understanding the effects on the magnetic ordering due to this additional valley degree of freedom. Specifically, I am interested in how fluctuations in the valley degree of freedom from one dot to the next can impact magnetic ordering.

What attracted you to Madison and the university?

There were two main reasons. First, my wife had gotten a residency as an anesthesiologist at the UW hospital. So that was an obvious motivation. Second, one of my grad school advisors knew Mark Eriksson and Mark Friesen and thought it’d be a natural fit for me to work with them as a postdoc. Since moving here, my family has enjoyed Madison, and I really like the physics department. The people are very friendly and collaborative. I am incredibly happy to be able to stay in Madison and at the UW physics department.

What is your favorite element and/ or elementary particle?

It has to be silicon, right? It’s the material I think about every day. And the world economy is largely based on stuff made with silicon. So that’s pretty cool?

What hobbies and interests do you have?

I like to play guitar, read, watch sports, and spend time with my family and friends. I have two kids, three years and six months old, who I like to spend most of my free time on.

Welcome, Prof. Elio König!

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Elio König

This fall, condensed matter theorist Elio König returned to Madison as an assistant professor of physics. König began his education in Germany and Italy, earning a PhD from the Karlsruhe Institute of Technology in 2014. He joined UW–Madison physics as a postdoc with Alex Levchenko, then completed a second postdoc at Rutgers University. Most recently, König held a group leader position at the Max Planck Institute of Solid State Research in Stuttgart, Germany.

Please give an overview of your research.

I’m a condensed matter theorist, so I study the collective behavior of quantum particles in materials. We study electronic collective behavior — behavior of electronic systems — and I study strong correlations in that regard. We do all of this with an eye on what’s happening in the quantum computation world. Our study of quantum materials can serve as a source of inspiration for building useful quantum devices in the context of quantum computers and potentially beyond.

And then reversely, the advances in quantum technology are of great use in our studying of quantum materials. We can use them as new probes, as new experimental techniques, and at the same time there is theoretical and conceptual cross-pollination. I’m inspired by these synergies.

What are one or two main projects your group will work on first?

The main directions that I’m heading in right now are 2D materials and trying to work more into concepts related to or at the interface between quantum materials and quantum information.

In the 2D world, what I’m really fascinated by is frustrated magnetism in these 2D materials, and in particular research on quantum spin liquids. Generally, the idea is to study states of matter beyond the standard concept of spontaneous symmetry breaking. We’re interested in topologically ordered states and quantum order, which is essentially based on the entanglement of many, many particles together. And these states of matter are relevant for topological quantum error correction codes. I think there’s also quite a lot of interest at UW already, both theoretically but also particularly experimentally, in 2D materials and I hope to collaborate with my future colleagues in that regard.

On the side of quantum materials and quantum information theory, there are ongoing projects that I want to extend on. I want to look for new setups for very robust quantum computers and topological quantum computation. At the same time, I want to use devices which are available right now for emulation of quantum many body systems.

What attracted you to Madison and the university?

This question is related to the question: why am I coming back to the States? I very much enjoyed my five years in the States, personally but also scientifically. The main aspect that I find more present in the States than in Europe is a more visionary approach to science. And I think this is also true for UW, so this is something that attracted me to UW. I know the department maybe better than other new faculty and it’s a fantastic place to work. I know that there are very inspiring colleagues, and I hope that there will be a chance to collaborate with them. And finally, Madison is a very nice place to live. I think it’s probably the nicest city of this size that I’ve seen in the States.

What is your favorite element and or elementary particle? [editor’s note: this interview was conducted via Zoom while König was on a cycling trip through the Italian Alps]  

I read some previous interviews, so I knew this question was coming. And when I was biking today, I was thinking about it. Given that I’m mountain biking in the Alps and it’s really intense, I decided that oxygen is the element I want to go for. I can’t get enough of it right now. Oxygen is of course a symbol for the life that humans and animals have on this planet. Finally, oxygen is also a symbol for the advances of science and scientific revolutions, for example Lavoisier’s pioneering work in this regard.

What hobbies and interests do you have?

I really enjoy biking — mountain biking and gravel biking in particular. This is the third time that I’m transversing the Alps. I got very much into dancing in the last three years in Stuttgart. I still dance forró, or Brazilian couple dancing, from time to time. I also like playing sports, particularly soccer and squash.

Mark Eriksson named Steenbock Professor

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This story was originally published by the Office of the Vice Chancellor for Research

Mark Eriksson, professor of physics, and Mikhail Feldman, professor of mathematics, have been named recipients of UW–Madison Steenbock Professorships.

“This professorship is among the most prestigious and important professorships for researchers at the UW–Madison,” says Cynthia Czajkowski, interim vice chancellor for research. “This recognition is accompanied by discretionary funds to provide recipients the freedom to explore innovative research directions and to explore new approaches to their research areas.”

In the early 1980s, Evelyn Steenbock initiated a program to endow a series of professorships in the natural sciences in honor of her late husband, Harry Steenbock, emeritus professor of biochemistry.

Harry Steenbock (1886-1967) developed an inexpensive method of enriching foods with Vitamin D. His discovery led to the eradication of rickets, the bone-deforming deficiency disease, throughout most of the world. He is also renowned for his discovery of the conversion of carotenes to vitamin A.

Steenbock assigned his patents for advances in human and animal nutrition to the Wisconsin Alumni Research Foundation (WARF), and accumulated royalties from Steenbock’s patents supplied about half the funds for the Steenbock Memorial Library construction on campus. Steenbock Memorial Library is a primary resource library for the students, faculty and research staff at the UW­–Madison.

The Steenbock Professorship provides research funds to recipients annually for 10 years and honors those faculty who have made major contributions to the advancement of knowledge, primarily through their research endeavors at UW­–Madison, but also as a result of their teaching and service activities.

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Mark Eriksson

Eriksson, awarded the Steenbock Professorship in the Physical Sciences, was recently chair of the Department of Physics. He joined the UW–Madison physics faculty in 1999 and is a world-leading expert in the development of quantum information systems using solid-state quantum dot qubits.

As department chair, Eriksson promoted the Wisconsin Idea by supporting the department’s role in connecting with audiences all around the state of Wisconsin, including restarting The Wonders of Physics Traveling Show.

Eriksson received a bachelor’s degree in physics and mathematics from UW–Madison in 1992, received his PhD from Harvard University and was a postdoctoral member of technical staff at Bell Labs.

His research has focused on quantum computing, semiconductor quantum dots and nanoscience. He leads a team dedicated to developing spin qubits in gate-defined silicon quantum dots with the goal of enabling quantum computers, which manipulate information coherently, to be built using many of the materials and fabrication methods that are the foundation of modern, classical integrated circuits.

Eriksson is widely recognized for engaging collaborative partnerships with industry, government leaders and other university research institutions to tackle some of the greatest challenges in quantum information science and technology. Last year, the Eriksson group announced its partnership with Intel and HRL Laboratories as part of the LPS Qubit Collaboratory (LQC) national Quantum Information Science Research Center hosted at the Laboratory for Physical Sciences at the University of Maryland, College Park to collaborate on research in advanced computer technologies.

“I intend to use the award to explore new opportunities in silicon-based quantum computing, including new ideas for connecting qubits to each other across large distances, and the use of near-atomic-scale metamaterials to endow semiconductors with properties even better suited to quantum computing than those available today,” Eriksson says.

Welcome, Professor Tiancheng Song!

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Tiancheng Song

Tiancheng Song, a condensed matter experimentalist, joined the UW–Madison Physics Department as an assistant professor on May 20. His research interest lies in two-dimensional (2D) quantum materials with a focus on 2D magnetism, 2D superconductivity and 2D topology. He joins us from Princeton University where he was a Dicke Fellow and won the Lee Osheroff Richardson Science Prize. He completed his PhD at the University of Washington and his bachelor’s degree from University of Science and Technology in China. He is originally from Tianjin, China, the son of two theoretical physicists.

Please give an overview of your research.

I work on experimental condensed matter physics and am especially interested in a new family of materials called two-dimensional materials, which resemble “Quantum LEGOs” at the atomic scale. These 2D materials can be exfoliated down to the monolayer limit just using Scotch tape, and each monolayer can act like a LEGO piece. This provides us with a full LEGO set of quantum materials in two dimensions, covering a broad spectrum of emergent quantum phenomena. Within this new material platform of condensed matter physics, I’m particularly interested in three topics: magnetism, superconductivity and topology. With the new tuning knobs uniquely enabled in this new material system, we aim to study these three topics in two dimensions using those LEGOs. There will be a lot of fun because we can use them like building blocks, stack them together like LEGO toys, and uncover new physics emerging from the toys we create!

What are the first one or two research projects you’ll work on when your group is running here?

Overall, we plan to discover new 2D quantum materials, develop new measurement techniques and explore new physics in this emergent platform. We aim to combine state-of-the-art nanofabrication of 2D materials with various measurement techniques including magneto-optics, quantum transport, thermoelectrics, optoelectronics, optical spectroscopy and microscopy. Our research will explore three directions: 2D magnetism, 2D superconductivity and 2D topology.

What attracted you to Madison and the University?

The University of Wisconsin–Madison is a top public university located in a beautiful city. The Department of Physics is renowned for its exceptional research in many areas of physics. My partner also works at UW–Madison.

What is your favorite element and/or elementary particle?

I usually say Chromium or Tellurium, but this time I would say Technetium (symbol Tc and atomic number 43). This is because my name is Tiancheng, and when I was a kid, my parents called me TC just for fun. Since studying abroad, I have found my name sometimes difficult to pronounce and remember for others, because it is a bit long and complicated. So, I started using this nickname again, and I’m happy to be called TC!

What hobbies and interests do you have?

I enjoy many sports, such as badminton, tennis and swimming. For those other sports that I am not very skilled at, I enjoy watching rather than playing.

Tiancheng Song awarded Lee Osheroff Richardson Science Prize

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This post is slightly adapted from one originally published by Oxford Instruments

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Tiancheng Song

Oxford Instruments announced Feb 15 that Tiancheng Song, who will join the UW–Madison physics department as an assistant professor in May, has been awarded the 2024 Lee Osheroff Richardson Science Prize. He is currently an experimental physicist and Dicke Fellow at Princeton University.

Dr. Song is recognized for his efforts in developing and employing various measurement techniques at low temperatures and in magnetic fields to study 2D superconductivity and magnetism in van der Waals heterostructures. His works have uncovered a series of emergent quantum phenomena in 2D superconducting and magnetic systems.

The Lee Osheroff Richardson Science Prize promotes and recognises the novel work of young scientists working in the fields of low temperatures and/or high magnetic fields or surface science in North and South America.

“I am thrilled to be the recipient of the prestigious Lee Osheroff Richardson Science Prize this year! I feel this is a special honour because I am joining the ranks of remarkable scientists who have been awarded this prize for their famous experiments and achievements,” commented Dr. Song.

Tiancheng Song is currently a Dicke Fellow in the Department of Physics at Princeton University. Working with Prof. Sanfeng Wu, Dr. Song recently developed a new technique to investigate 2D superconductivity, strongly correlated phases and the associated unconventional quantum phase transition.

In his work at Princeton, Dr. Song successfully measured superconducting quantum fluctuations of monolayer WTe2 based on the vortex Nernst effect. The result led to the discovery of a new type of quantum critical point beyond the conventional Ginzburg-Landau theory and demonstrated a new sensitive probe to 2D superconductivity and superconducting phase transitions.

Dr. Song’s results have been well recognized by the community with his work being cited over 4,000 times. Dr. Song’s original contributions are demonstrated by the faculty offers he has subsequently received; he will join the University of Wisconsin–Madison as an assistant professor in May 2024.

As part of the prize, Dr. Song will receive $8000 as well as support to attend the APS March Meeting in Minneapolis where he will be presented his award.

The 2024 LOR Science Prize selection committee is chaired by Professor Laura Greene, NHMFL and FSU and includes: Professor Hae-Young Kee, Toronto University; Professor Collin Broholm, Johns Hopkins University; Professor Paula Giraldo-Gallo, University of the Andes; and Dr Xiaomeng Liu, Princeton (2023 winner).

About the LOR Science Prize

Oxford Instruments is aware that there is a critical and often difficult stage for many scientists between completing a PhD and gaining a permanent research position. The company is pleased to help individuals producing innovative work by offering financial assistance and suitably promoting their research work, through sponsoring the LOR Science Prize for North and South America for the past 19 years. The Prize is named in honour of Professors David M. Lee, Douglas D. Osheroff and Robert C. Richardson, joint recipients of The Nobel Prize in Physics 1996 for their discovery of ‘superfluidity in helium-3’.

The previous winners of the LOR Science Prize are Dr Xiaomeng Liu, Dr James Nakamura, Dr Matthew Yankowitz, Dr Sheng Ran, Dr Paula Giraldo-Gallo, Dr Kate Ross, Dr Brad Ramshaw, Dr Mohamad Hamidian, Dr Cory Dean, Dr Chiara Tarantini, Dr Lu Li, Dr Kenneth Burch, Dr Jing Xia, Dr Vivien Zapf, Dr Eunseong Kim, Dr Suchitra Sebastian, Dr Jason Petta, and Dr Christian Lupien.

A new spin on an old superconductor means that it can be an ideal spintronic material, too

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Back in the 1980s, researchers discovered that a bismuthate oxide material was a rare type of superconductor that could operate at higher temperatures. Now, a team of engineers and physicists at the University of Wisconsin-Madison has found the material, “Ba(Pb,Bi)O3,” is unique in another way: It exhibits extremely high spin orbit torque, a property useful in the emerging field of spintronics.

The combination makes this and similar materials potentially important in developing the next generation of fast, efficient memory and computing devices.

The finding was an encouraging surprise to Chang Beom-Eom, a professor of materials science and engineering, and Mark Rzchowski, a professor of physics, both at UW-Madison. “We’re looking to expand the range of materials that can be used in spintronic applications,” says Rzchowski. “We had known from previous work these oxides have a lot of interesting properties, and so were investigating the spintronic characteristics. We weren’t anticipating such a large effect. The origins of this are not theoretically understood, but we can speculate about some interesting physical mechanisms.”

The paper was published Dec. 5, 2023, in the journal Nature Electronics.

In conventional electronics, positive and negative electric charges are used to flip millions or billions of tiny transistors on semiconductor chips or in memory devices. But in spintronics, magnetic fields, and interactions with other electrons, manipulate a fundamental property of electrons called the spin state, which records information. This is much faster, more energy-efficient and more powerful than current semiconductors and will advance the development of quantum computing and low-power devices.

Read the full story

 

Featured image caption: Chang Beom-Eom, a professor of materials science and engineering, and Mark Rzchowski, a professor of physics, in the lab. Photo: Joel Hallberg.

Ben Woods and team named finalists in 2023 WARF Innovation Awards

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Each fall the WARF Innovation Awards recognize some of the best inventions at UW–Madison. WARF receives hundreds of new invention disclosures each year. Of these disclosures, the WARF Innovation Award finalists are considered exceptional in the following criteria:

  • Has potential for high long-term impact
  • Presents an exciting solution to a known important problem
  • Could produce broad benefits for humankind

One of the six finalists comes from Physics. Research Associate Benjamin Woods and a team including Distinguished Scientist Mark Friesen, John Bardeen Prof. of Physics Mark Eriksson, Honorary Associate Robert Joynt, and Graduate Student Emily Joseph developed a quantum device that shows a significant increase in valley splitting, a key property needed for error-free quantum computing. The device features a novel structural composition that turns conventional wisdom on its head.

Two winners, selected from the six finalists, will be announced in WARF’s annual holiday greeting; sign up to receive the greeting here. Each of the two Innovation Award winners receive $10,000, split among UW inventors.

Victor Brar earns NSF CAREER award

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Congrats to associate professor Victor Brar on earning an NSF CAREER award! CAREER awards are NSF’s most prestigious awards in support of early-career faculty who have the potential to serve as academic role models in research and education and to lead advances in the mission of their department or organization.

Victor Brar

For this award, Brar will study the flow of electrons in 2D materials, or materials that are only around one atom thick. His group has already shown that when they applied a relatively old technique — scanning tunneling potentiometry, or STP — to 2D materials such as graphene, they could create unexpectedly high-contrast images, where they could track the movement of individual electrons when an electric current was applied. They found that electrons flow like a viscous fluid, a property that had been predicted but not observed directly.

“So now instead of applying electrical bias, we’ll apply a thermal bias, because we know things move from hot to cold, and then image how [electrons] move in that way,” Brar says. “Part of what’s driving this idea is that Professor Levchenko has predicted that if you image the way heat flows through a material, it should also behave hydrodynamically, like a liquid, rather than diffusive, which is how you might imagine it.”

One motivation for this research is to better understand the general flow of fluids, a problem that is often too complex for supercomputers to solve correctly. Because STP visualizes the fluid-like flow of electrons directly, Brar envisions this work as potentially providing a way of solving  fluid mechanics problems by directly imaging flow, without the need of simulations, similar to what is done in wind tunnels.

“Also, there are these predicted phases of electrons that no one has observed before,” Brar says. “We want to be the first to observe them.”

In addition to an innovative research component, NSF proposals require that the research has broader societal impacts, such as working toward greater inclusion in STEM or increasing public understanding of science. Brar’s group is using haptic pens, devices that are commonly used in remote trainings for surgeons and in the gaming community because they give a gentle push back that mimics a realistic touch. By attaching the haptic pen to a scanning tunneling microscope (STM), people holding the pen can “feel” the individual atoms and surfaces that the STM is touching.

“We think materials science is one of those areas where feeling the forces that hold matter together may provide more intuitive than looking at equations,” Brar says. “We’re making virtual crystal lattices that you can touch with the haptic pen and feel how the atoms fix together, but we’re also making it so you can feel the different forces of the different atoms used.”

Brar plans to introduce the haptic pen and atom models into Physics 407 and develop a materials science module for the UW Alumni Association’s Grandparents University. And because the haptic pen relies almost entirely on touch, Brar plans to work with the Wisconsin Council of the Blind and Visually Impaired to improve access to materials science instruction for people with vision impairments.

 

 

Congrats to Prof. Joynt on his retirement!

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37 years after joining the faculty of the department of physics at the University of Wisconsin–Madison, Prof. Bob Joynt has announced his retirement at the end of July.

Joynt is a condensed matter theorist who began as an assistant professor in 1986. His early work focused largely on superconductivity, including high temperature superconductors. He also played an important role in better understanding the Quantum Hall effect, dating back to his graduate work and continuing here. After a decade and a half, his career took a fortuitous turn when he wrote a quantum computing grant proposal with physics professor Mark Eriksson and other researchers in engineering.

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Prof. Bob Joynt

“That was really a pivotal point in my career, and I’ve been doing quantum computing mostly ever since,” Joynt recalls. “Change is good, I found. I enjoyed that change and I’m glad I did it.”

His work for the past 20 years has mainly focused on understanding the origins of noise and decoherence in quantum systems and in the design of semiconductor structures for quantum computing. Joynt is a fellow of the American Physical Society and a UW–Madison Romnes Faculty Fellow. He has co-authored over 175 peer-reviewed publications and trained 26 doctoral students, in addition to numerous postdocs and MS Physics­–Quantum Computing students.

Joynt’s academic and research achievements alone comprise an illustrious career that any retiring professor would likely be happy with. Still, his contributions to the department span so much more.

Joynt served as department chair from 2011-2014, for which he focused his efforts on department fundraising. He was responsible for starting the Board of Visitors, a group of people, mostly in industry, with strong ties to the department. The BoV advises and assists on department priorities, plays a leading role in fundraising, and provides a professional network for current students and alumni. From 2017-2022, Joynt additionally served as the department’s Associate Chair for Alumni Relations and the Board of Visitors.

a man stands near a white board looking at an unpictured audience. He is holding a wood pointer in his right hand and gesturing with his left hand.
Prof. Joynt lectures in this undated photo from earlier in his career

Around 2016, Joynt noted that doctoral students with quantum computing research experience were in such high demand that employers were often entering bidding wars for them. Was there a way to meet the demands of the quantum computing workforce by training students in a year or two? And so, thanks to Joynt’s vision and persistence, the MS in Physics–Quantum Computing program — the first MS in quantum computing in the U.S. — enrolled its first cohort in Fall 2019.

“We take about 25-30 PhD students each year, and now we take about the same number of MSQPC students,” Joynt says. “It’s become a big part of the department’s educational program.”

Adds Mark Eriksson, Department Chair and John Bardeen Professor of Physics: “Our department’s MSPQC program was the first in the nation and remains a model for others, thanks to Professor Joynt’s vision and energy.”

The department boasts the oldest hands-on science museum in the country — a claim we now feel confident making thanks to Joynt’s extensive research on the history of the Ingersoll Physics Museum for its 100th anniversary in 2018. The museum and physics outreach in general have always been important to Joynt. He has served in an informal capacity as faculty lead for the museum for several years now, helping to raise funds and ensure the museum fulfills its mission of providing free, hands-on, inquiry-based exhibits.

When asked what he wanted to be remembered for in the department, Joynt reflected on lessons from his career and then looked forward: “My advice to the department is: do new things. Don’t be afraid of change. Science changes, education changes, all these things are changing, and you need to change with them.”

Joynt’s retirement is official as of July 31, but he emphasizes that he is only retiring from administrative and teaching duties. He plans to continue his research efforts, sometimes in Madison and often abroad.

Mark Friesen, a senior scientist and long-time collaborator of Joynt’s, says he looks forward to continuing to work with Joynt in this new stage of his career, adding:

“When I joined the department, I knew Bob through reputation as one of the bright condensed matter physicists of his generation. I feel very fortunate to have worked with him, first as a mentor, and later as a colleague. Bob has a tremendous intuition for condensed matter that spans far beyond his immediate research efforts. He also has an easy-going and gracious style that draws in collaborators, and he is just fun to interact with, both inside and outside the department.”