Zhaoyu Han's Research Homepage

Zhaoyu Han 韩兆宇

PhD candidate at the Department of Physics

Stanford University

E-mail: zyhan_at_stanford.edu

Biographical Information

Employment

Harvard University, Sep. 2024 – present

- Postdoctoral Fellow, host: Prof. Ashvin Vishwanath

Education

Leland Stanford Junior University, Sep. 2018 – Sep. 2024

- Ph.D. candidate in Physics, advisor: Prof. Steven Allan Kivelson

Peking University, Sep. 2014 – July 2018

- B.S. in Theoretical Physics

Main Research Topics

(see below for relevant references)

Exotic phases in strongly coupled electron-phonon systems
- Resonating valence bonds states [12]
- Pair density waves and valley polarization [5, 6, 9, 19]
- Light bipolaron superconductivity [13, 16]
- Charge 4e/6e superconductivity [5]
Flat band/moire systems
- "Quantum geometric nesting" and solvable model flat-band systems [18]
- Violation of Pauli limit and reentrant superconductivity at high Zeeman field in valley polarized systems [9]
(Fractional) quantum Hall physics
- Solvable lattice Hamiltonians with FQH coefficients [7, 10]
- A two-fluid description mixing composite boson and composite fermion perspectives [14]
- Quantum Hall ferromagnetism in magic-angle twisted bilayer graphene [8] and monolayer WSe2 [17]
Interdisciplinary study of quantum information & machine learning
- Generative modeling with tensor network states [2]
- Efficient quantum state tomography [3]

Besides the above topics, I am also broadly interested in phase transitions with topological characters, High-Tc superconductivity, topological quantum computation/simulation, and non-equilibrium physics. Always happy to chat about any of these with theory and experiment friends!

Publication List

Google Scholar / ArXiv

(anti-chronological order, *asterisked authors contribute equally)

19. Jiucai Wang, Wen Sun, Hao-Xin Wang, Zhaoyu Han, Steven A. Kivelson, Hong Yao. Pair density waves in the strong-coupling two-dimensional Holstein-Hubbard model: a variational Monte Carlo study. arXiv: 2404.11950

18. Zhaoyu Han, Jonah Herzog-Arbeitman, B. Andrei Bernevig, Steven A. Kivelson. "Quantum Geometric Nesting'' and Solvable Model Flat-Band Systems. arXiv: 2401.04163.

17. Benjamin A. Foutty, Vladimir Calvera, Zhaoyu Han, Carlos R. Kometter, Song Liu, Kenji Watanabe, Takashi Taniguchi, James C. Hone, Steven A. Kivelson, Benjamin E. Feldman. Anomalous Landau level gaps near magnetic transitions in monolayer WSe2. arXiv: 2401.01486.

16. Zhaoyu Han, Steven A. Kivelson, and Pavel A. Volkov. "Quantum bipolaron" superconductivity from quadratic electron-phonon coupling. arXiv: 2312.03844.

15. Fangze Liu and Zhaoyu Han. Pair-density-wave and s±id superconductivity in a strongly coupled, lightly doped Kondo insulator. Phys. Rev. B 109, L121101 (2023) (Letter). arXiv: 2310.17691

14. Zhaoyu Han, Kyung-Su Kim, Steven A. Kivelson, and Thors Hans Hansson. Two-fluid theory of composite bosons and fermions and the quantum Hall proximity effect. Phys. Rev. B 108, 195117 (2023). arXiv: 2308.10190

13. Kyung-Su Kim*, Zhaoyu Han*, John Sous. Semi-classical theory of bipolaronic superconductivity in a bond-modulated electron-phonon model. arXiv: 2308.01961

12. Zhaoyu Han and Steven A. Kivelson. Resonating valence bond states and other surprises in an electron-phonon system. Phys. Rev. Lett. 130, 186404 (2023). arXiv: 2210.16321

11. Sijia Zhao, Zhaoyu Han, Ilya Esterlis, and Steven A. Kivelson. The one-dimensional Holstein model revisited. Phys. Rev. B 107, 075142 (2023). arXiv: 2209.05498

10. Zhaoyu Han and Jing-Yuan Chen. Fractional Hall conductivity and spin-c structure in solvable lattice Hamiltonians. J. High Energ. Phys. 2023, 130 (2023). arXiv: 2208.13785

9. Zhaoyu Han and Steven A. Kivelson. Pair density wave and re-entrant superconducting tendencies originating from valley polarization. Phys. Rev. B 105, L100509 (2022) (Letter, Editor’s Suggestion). arXiv: 2112.03278

8. Jiachen Yu, Benjamin A Foutty, Zhaoyu Han, Mark E Barber, Yoni Schattner, Kenji Watanabe, Takashi Taniguchi, Philip Phillips, Zhi-Xun Shen, Steven A Kivelson, and Benjamin E Feldman. Correlated Hofstadter spectrum and flavour phase diagram in magic-angle twisted bilayer graphene. Nat. Phys. 18, 825–831 (2022). arXiv: 2108.00009

7. Zhaoyu Han and Jing-Yuan Chen. Solvable lattice Hamiltonians with fractional Hall conductivity. Phys. Rev. B 105, 155130 (2022). arXiv: 2107.02817

6. Kevin S. Huang*, Zhaoyu Han*, Steven A. Kivelson, and Hong Yao. Pair-density-wave in the strong coupling limit of the Holstein-Hubbard model. npj Quan. Mater. 7, 17 (2022). arXiv: 2103.04984

5. Zhaoyu Han, Steven A. Kivelson, and Hong Yao. Strong coupling limit of the Holstein-Hubbard model. Phys. Rev. Lett. 125, 167001 (2020). arXiv: 2006.16253

4. Zhaoyu Han, Shiwei Zhang, and Xi Dai. Charge density waves in a quantum plasma. Phys. Rev. B 100, 155132 (2019). arXiv: 1910.07152

3. Jun Wang*, Zhaoyu Han*, Song-Bo Wang, Zeyang Li, Liang-Zhu Mu, Heng Fan, Lei Wang. Scalable quantum tomography with fidelity estimation. Phys. Rev. A 101, 032321 (2020). arXiv: 1712.03213

2. Zhaoyu Han*, Jun Wang*, Heng Fan, Lei Wang and Pan Zhang. Unsupervised generative modeling using matrix product states. Phys. Rev. X 8, 031012 (2018). arXiv: 1709.01662

1. Bing-Tian Ye*, Zhaoyu Han*, Liang-Zhu Mu and Heng Fan. Investigating disordered many-body system with entanglement in momentum space. Sci. Rep. 7, 16668 (2017). arXiv: 1607.05877

Talk slides

Solvable Lattice Hamiltonians with Fractional Hall Conductivity, Princeton, May 2023.
"Spin Liquids" and Exotic Superconductivity in Strongly Coupled Electron-Phonon Systems, Flatiron Insititute, May 2023; Harvard, June 2023.
Pair-Density-Wave in the Strong Coupling Limit of the Holstein-Hubbard Model, KITP, May 2022; Cornell (online), June 2021.
Machine Learning a Quantum State, Anqing Normal University (China), Nov. 2017.