中法核工程与技术学院核声论坛（总第201期）

报告摘要：

Calculating interacting many-fermion systems remains one of the central challenges in modern theoretical physics. We propose novel Quantum Monte Carlo (QMC) methods for general many-fermion systems by leveraging the stochastic gauge freedom, originally developed in Gaussian phase-space QMC, within the phaseless auxiliary-field QMC (AFQMC) framework. We reinterpret the conventional force bias in AFQMC as a drift gauge and explore Fermi gauges based on natural orbitals of a reduced one-body density matrix defined via a mixed estimator, yielding stochastic, time-dependent Hartree-Fock or Hartree-Fock-Bogoliubov-like dynamics. As proof of concept, these gauge-augmented AFQMC schemes are investigated using a minimal shell-model Hamiltonian for nuclear pairing. Numerical results demonstrate the potential of stochastic gauges to balance statistical precision, systematic bias, and numerical stability, opening new avenues for improving AFQMC performance. The systematically improvable accuracy via stochastic gauges and trial wave functions underscores the promise for advancing AFQMC toward realistic dripline nuclear shell-model calculations.

主讲人简介：

ZHANG Zhaozhan, completed his Bachelor's and Master's degrees at Sino-French Institute of Nuclear Engineering and Technology, Sun Yat-Sen University. And he will receive his Ph.D. from the University of Tokyo. His research interests are Nuclear many-body theory, quantum Monte Carlo methods, strongly correlated fermions, computational physics and algorithms.