Department of Physics
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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.

Baha Balantekin wins 2025 APS Bethe Prize

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Baha Balantekin

Congrats to Prof. Baha Balantekin on winning the American Physical Society’s 2025 Hans A. Bethe prize!

The Bethe prize is awarded to recognize outstanding work in theory, experiment or observation in the areas of astrophysics, nuclear physics, nuclear astrophysics, or closely related fields. Balantekin won “for seminal contributions to neutrino physics and astrophysics — especially the neutrino flavor transformation problem — both for solar neutrinos and the nonlinear supernova environment.”

Balantekin works at the intersection of particle physics, nuclear physics, and astrophysics. For much of his career, he has studied theoretical aspects of neutrino transport originating in the Sun, supernovae, or neutron star mergers.

“The concepts (I brought to the field) were marrying neutrino physics with many-body physics,” Balantekin says. “Of course, incorporating many-body aspects is common in condensed matter and nuclear physics, but it’s not as common in environments studied in astrophysics.”

Several fundamental astrophysical processes produce neutrinos as byproducts, and scientists have been studying neutrino origins and patterns for decades. Detecting the Sun’s neutrinos can reveal insights into its nuclear reactions, for example, and detecting neutrinos from core collapse supernovae can reveal insights into the early universe.

Balantekin’s early research was on the theory of neutrino transport from the Sun. He has also been studying core collapse supernovae, the result of a star running out of nuclear fuel. During collapse, a very hot star cools very quickly, emitting neutrinos on the order of 10^58.

“A number of that magnitude means you can no longer ignore the neutrino-neutrino interactions,” Balantekin says. “And then it becomes a very interesting many-body problem, where you have two-body interactions between neutrinos, and the propagation, and then it becomes a very complex problem.”

black and white group photo from 1995. There are 7 men featured
Balantekin and department collaborators in 1995. Balantekin is seated, right. Seated next to him is former PhD student Alan DeWeerd. Standing row, L-R: Franco Ruggeri, John Beacom, Jonathan Fetter, late physics professor Kirk McVoy, and William Friedman.

To describe this problem, has more recently begun using techniques from quantum information science to study entanglement of neutrinos with each other and to look at the signatures of such interactions and how they might contribute to heavy element formation.

The Bethe Prize was awarded solely to Balantekin, but he says he would not have won it without his collaborators over the years.

“You don’t do work in a vacuum,” Balantekin says. “I’ve worked with a lot of very talented young people. I would like to acknowledge first not only my graduate students at Wisconsin, but also the Fellows who came from the N3AS Physics Frontier Center we have. And the people I collaborate with around the world. We also have colleagues here in the department like Sue Coppersmith and Mark Saffman who contributed many ideas.”

The Bethe prize consists of $10,000 and a certificate citing the contributions made by the recipient. It is presented annually.

Britton Plourde elected Fellow of the American Physical Society

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Britton Plourde (credit: Syracuse University)

Congratulations to Prof. Britton Plourde for being elected a Fellow of the American Physical Society!

Plourde was elected “For important contributions to the physics and operation of superconducting qubits, including the development of techniques for scalable qubit control and readout, and investigations of decoherence from vortices and nonequilibrium quasiparticles.” He was nominated by the Division of Quantum Information Fellowship.

APS Fellowship is a distinct honor signifying recognition by one’s professional peers for outstanding contributions to physics. Each year, no more than one half of one percent of the Society’s membership is recognized by this honor.

See the full list of 2024 honorees at the APS Fellows archive.

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.

Rogerio Jorge receives first grant as a professor

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Rogerio Jorge

Congrats to Prof. Rogerio Jorge who was awarded his first grant as a professor! The three-year, $500,000 National Science Foundation grant, titled “Moment Approach to Multiscale Plasmas,” will be used to fund a graduate student and postdoc on the project.

“Astrophysical plasmas appear in more than 90% of the universe — for example, on the surface of the sun or in the intergalactic medium — and there’s still a lot of things that we don’t understand about them,” Jorge says. “We need to study phenomena in astrophysical plasmas and try to replicate them numerically to better understand them.”

Jorge’s work will focus on the so-called collisionless regime of these plasmas, where particles travel for a long time before experiencing any collision. He says this regime is difficult to model, both experimentally and numerically.

“We’ve proposed a new method that has two parts. The first one is to try to simplify the equations using a reduced model, called a moment model,” Jorge says. “Second, it’s using machine learning to reduce it even more.”

Jorge and his team have the moment model theory ready to be applied. For the machine learning step, they will use JAX, an open-source machine learning framework developed by the DeepMind team at Google that many physicists are starting to use in their research.

Jorge plans to investigate one intriguing phenomenon in collisionless plasmas: how the acceleration of super-thermal particles occurs versus thermodynamic heating. This will help scientists understand how charged particles in a plasma become energized, a phenomenon applicable to both laboratory and astrophysical plasmas. He will also apply this new approach to the problem of magnetic reconnection in collisionless plasmas, a problem he says is difficult to model due to the topology changes that occur in short time scales.

“We need new models to try to handle these complex scenarios without spending months and months on a single simulation,” Jorge says.

NSF grants require investigators to address the broader impacts of their research, defined as “the potential to benefit society and contribute to the achievement of specific, desired societal outcomes.” Jorge plans to work with the department’s Wonders of Physics outreach program to create realistic movies that simulate these astrophysical plasma environments. For example, he hopes to show, in detail, what is happening with magnetic reconnection in auroras or around the surface of the sun, with both using the new code developed through his research.

For this research, Jorge is collaborating with experimentalists at UW-Madison’s WiPPL facilities, and computational plasma physicists at UCLA, MIT, and Princeton.

New Chair to continue department’s strengths, commit to diversity and inclusion

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Prof. Kevin Black

The department of physics is pleased to announce that Prof. Kevin Black has been named new department chair. His three-year term began July 1, 2024, succeeding Prof. Mark Eriksson. Black says he is looking to continue the department’s excellence in its mission of research, teaching, and outreach, and to continue developing an intentional commitment to diversity.

“Under Prof. Eriksson’s leadership, our department has attained near-record highs of faculty members as well as graduate and undergraduate students, which will lead to significant successes in our research program,” Black says. “Now, we need to continue to focus on making a commitment to diversity an active component of what we do as a department.”

Two pillars of the department’s mission have always been research and teaching, and Black wants to sustain successes in those areas. He begins his term with over a dozen faculty members who have joined the department in the previous three years, bringing the total number of professors to 56. These faculty members represent a range of seniority levels and a breadth of research fields. He also begins at a time when more students than ever are being taught in department courses.

“Research and education are the core values of a research university,” Black says. “We want to do excellent, cutting-edge research and we want to teach the next generation of scientists.”

Black’s focus on diversity and climate efforts represents a continuing effort from leadership before him. The need to add diversity as a pillar of the department’s mission became evident to him when he saw the list of department chairs who came before him, and he noted that he was the 33rd white male chair out of 35. He acknowledges the challenge that the broader field of physics faces, and specifically at UW–Madison: both lack adequate representation of students from marginalized groups.

“We need to improve diversity at all levels in this department,” Black says. “There’s no magic wand. It takes a concerted, sustained effort and we need to make it a priority going forward.”

Lastly, Black also believes that the department’s commitment to educational outreach is critical to fulfilling the Wisconsin Idea, the idea that education should influence people’s lives beyond the boundaries of the university. The department has a long-standing tradition of engaging in outreach, including over 100 years of running the Physics Museum and over four decades of running The Wonders of Physics outreach program.

“Physics outreach can inspire the next generation to think about the natural universe and think about how things work,” Black says. “In a world which is increasingly driven by soundbites and nonsense on the internet, it’s crucial to encourage and guide young students to think rationally about science and formulate questions and opinions.”

Black joined the faculty as a full professor in 2018 and works with the high energy experiment group on the Compact Muon Solenoid (CMS) experiment at CERN. He had previously been a professor at Boston University. Black earned a bachelor’s degree at Wesleyan University where he worked in an atomic physics lab. He has a doctorate in physics from Boston University, and much of his thesis work was completed on the Tevatron at Fermilab. He was then a postdoc and research scientist at Harvard University, where his work transitioned to the Large Hadron Collider at CERN.

Daniel Den Hartog earns Progress Award from Laser Society of Japan

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Congrats to plasma scientist Daniel Den Hartog who is part of a team that was recently awarded a Progress Award from the Laser Society of Japan. This award is given to research that has shown a significant impact on the advancement of laser engineering.

The work was led by Ryo Yasuhara of the National Institute for Fusion Science in Japan. The team was recognized for “research on transient plasma electron and temperature distribution measurement by Thomson scattering method using a repetitive 20 kHz, 1.2 J, nanosecond laser.”

The Progress Award was one of a handful awarded recently by the Laser Society of Japan. For a full list, see LSJ’s awards site.

Separate research groups push fusion plasma performance to new levels

Two teams of scientists have announced a breakthrough in fusion energy research, demonstrating for the first time the ability to simultaneously achieve high plasma density and confinement in a tokamak reactor. Derived from a Russian acronym, a tokamak is a donut-shaped experimental device that uses magnetic fields to make use of the energy of nuclear…

The post Separate research groups push fusion plasma performance to new levels appeared first on Research & Development World.

Read the full article at: https://www.rdworldonline.com/separate-research-groups-push-fusion-plasma-performance-to-new-levels/