Kevin Zhou

Biography

I’m a postdoctoral researcher at UC Berkeley and LBNL, working at the Berkeley Center for Theoretical Physics. I am primarily interested in accelerating the discovery of physics beyond the Standard Model through new kinds of precision experiments. Many of these ideas focus on detecting ultralight dark matter, though I’ve also thought about more radical possibilities, such as modifications of long-range forces due to continuous spin. A complete CV is available here.

Previously, I earned my PhD degree at Stanford in 2024, and Master’s degrees at Cambridge and Oxford. During that period I spent a lot of energy on physics education and outreach, and I’m still always interested in hearing a good physics puzzle. For research-related inquiries, you can reach me at kzhou7@berkeley.edu, and for everything else, try kzhou7@gmail.com.

Recent Papers

F. Day, R. Harnik, Y. Kahn, S. Pavaskar, K. Zhou

November 2025

Quantum Calculations of the Cavity Shift in Electron Magnetic Moment Measurements

Conducting walls have a very small, but observable effect on measurements of electron $g-2$. We compute it from first principles with quantum field theory, and show how it can be accounted for in future measurements.

arXiv Talk slides Talk video

Y. Bao, D. Y. Cheong, N. Rodd, J. Takach, L.-T. Wang, K. Zhou

October 2025

Intrinsically Quantum Effects of Axion Dark Matter are Undetectable

Intrinsically quantum effects of axion dark matter are always highly suppressed, and in practice undetectable. Thus, even though the axion may be in a nonclassical state, it can still be treated as a classical field.

arXiv Talk slides

Z. Li, K. Zhou, M. Oriunno, A. Berlin, S. Calatroni, R. Tito D’Agnolo, S. Ellis, P. Schuster, S. Tantawi, N. Toro

July 2025

A Prototype Hybrid Mode Cavity for Heterodyne Axion Detection

The heterodyne approach to axion detection enhances the axion signal power. A prototype cavity was designed and tested, with a novel geometry that maximizes signal, suppresses noise, and allows a wide tuning range.

arXiv Talk slides

A. Berlin, A. Millar, T. Trickle, K. Zhou

April 2025 Phys. Rev. D

Determining Spin-Dependent Light Dark Matter Rates from Neutron Scattering

Light dark matter particles could couple directly to electron spin. Since the same is true for neutrons, existing neutron scattering data can accurately predict the signal rate of a dark matter experiment.

arXiv Phys. Rev. D Talk slides

K. Zhou

February 2025 JHEP

Ponderomotive Effects of Ultralight Dark Matter

Oscillating forces, torques, and mass shifts from dark matter average to zero, but can yield a nonzero second order effect enhanced at low frequency, analogous to the ponderomotive force or gravitational wave memory.

arXiv JHEP

See all publications

Teaching

Quantum Field Theory I (Physics 330)

In Autumn 2022, I was the TA for Stanford’s introductory quantum field theory class, taught by Prof. Bernhard Mistlberger. We overhauled the course and produced new problem sets, which we believe strike a good balance between traditional particle physics applications, and connections to other fields. I also taught weekly sections which laid out the big picture and showed tricks for doing the problems efficiently.

Problem sets: 1, 2, 3, 4, 5, 6, 7, 8, 9 | Solutions: 1, 2, 3, 4, 5, 6, 7, 8, 9
Very rough section notes: 1, 2, 3, 4, 5, 6, 7, 8, 9, 10
Final exam | Solutions

Physics Olympiad Handouts

In 2019 and 2021–2024, I coached the US Physics Team and wrote many of its exam questions and solutions, while developing a comprehensive set of training material. These handouts are the result. They contain full explanations of all the problem solving techniques used in the USAPhO and IPhO, hundreds of illustrative examples, and about 1,000 tough problems, with solutions. For more details, see the syllabus and FAQ. Usually, students take a year to work through the handouts; to see if you’re ready, try the preliminary problems (answers here).

Core Curriculum

Problem Solving I (Sol), Problem Solving II (Sol)
Mech I (Sol), Mech II (Sol), Mech III (Sol), Mech IV (Sol)
Elec I (Sol), Elec II (Sol), Elec III (Sol), Elec IV (Sol)
Mech V (Sol), Mech VI (Sol), Mech VII (Sol)
Thermo I (Sol), Thermo II (Sol), Thermo III (Sol)
Elec V (Sol), Elec VI (Sol), Elec VII (Sol)
Relativity I (Sol), Relativity II (Sol)
Waves I (Sol), Waves II (Sol), Modern I (Sol)

Supplemental Topics, Review, and Practice Olympiads

Mech VIII (Sol), Elec VIII (Sol), Relativity III (Sol)
Waves III (Sol), Modern II (Sol), Modern III (Sol)
Mech Review (Sol), Elec Review (Sol), Other Review (Sol)
USAPhO-M (Sol), USAPhO-E (Sol), USAPhO-X (Sol)
USAPhO-A (Sol), USAPhO-B (Sol), USAPhO-C (Sol), USAPhO-D (Sol)
Expt (Sol), Final (Sol)

I retired from coaching in 2024, and am no longer involved in writing or editing the F=ma and USAPhO; direct inquiries to AAPT. For Russian translations of the handouts, see Physics Hub.

Personal Notes

These are the notes I’ve taken while learning physics. I use them for reference, but they’re quite terse, and not a good resource to learn from. They weigh in at 1,900 pages and 750,000 words.

Undergraduate

These notes cover what I learned at MIT, through courses, lecture notes, and books.

Graduate

These notes follow courses taught at Cambridge’s Part III and Oxford’s MMathPhys.

If you like the style, you can download a TeX template here.

Writing

Advice

Learning Introductory Physics. A FAQ for high school students who want to start learning physics or taking part in physics competitions, such as the USAPhO.
After Introductory Physics. Some tips for self-taught students on what to do after mastering the basics, including book recommendations and online resources.
Physics Activities. Some places you can apply your physics knowledge in high school.
The Theoretical Minimum. A short list of canonical books you could self-study, to go from the level of introductory physics to PhD candidacy.
The Stanford Physics Qualifying Exam. A transcript of my PhD qualifying exam, and advice.

Expository

The Surprising Subtlety of Electrostatic Field Lines. A fun puzzle in electrostatics and its resolution with differential geometry; coauthored with Tomas Brauner.
Novel Searches for Physics Beyond the Standard Model. My Stanford PhD dissertation, covering several new types of experimental searches, and their motivation.
Cosmological Relaxation. My Oxford MSc dissertation, reviewing models that “relax” the Higgs boson’s mass, and motivations for model building.
The Meaning of Nothing. The New College Demuth prize essay, on how theoretical stories map onto reality, and why a physicist’s philosophical flexibility is a useful tool. Published in the New College Record with a wonderful illustration by Audrey Effenberger.

Links

Here are some memorable articles about science and everything else.
Here are some fun videos for a rainy day.
My 1,000 answers on Physics StackExchange have 2.5 million views; here’s a sample.