Quantum Monte Carlo Simulations for 2D Moiré Flat Bands

ORAL

Abstract

We report a study about moiré flat bands superconductor by projecting Coulomb repulsion and phenomenological attraction onto flat bands. Exact solution at flat band limit and Quantum Mento Carlo (QMC) results for finite band width are shown. With the development of fermion sign bounds theory for QMC, we show the polynomial decay of sign problem in chiral flat band twisted bilayer graphene at integer fillings so that finite temperature characters are ready to study in this limit with affordable sign problem.

*This report is funded in part by a QuantEmX grant from ICAM and the Gordon and Betty Moore Foundation through Grant GBMF9616 to Xu Zhang. I thank HPC2021 system under the Information Technology Services and the Blackbody HPC system at the Department of Physics, the University of Hong Kong for their technical support and generous allocation of CPU time.

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Publication: 1. X Zhang, K Sun, H Li, G Pan, ZY Meng - arXiv preprint arXiv:2111.10018, 2021
2. X Zhang, G Pan, XY Xu, ZY Meng - Physical Review B, 2022
3. In preparation

Presenters

  • Xu Zhang

    • The University of Hong Kong

Authors

  • Xu Zhang

    • The University of Hong Kong

  • Kai Sun

    • University of Michigan

  • Zi Yang Meng

    • HKU, Department of Physics, Pokfulam Road, Hong Kong
    • The University of Hong Kong
    • Hong Kong University

  • Gaopei Pan

    • Institute of Physics, Chinese Academy of Sciences

  • Heqiu Li

    • University of Toronto

  • Xiao Yan Xu

    • Shanghai Jiao Tong University

  • Bin Bin Chen

    • The University of Hong Kong