报告题目：Diagrammatic Monte Carlo Method for Correlated System

报 告 人：邓友金，中国科学技术大学

报告时间：2016年8月19日15：00

报告地点：理科楼B315

报告摘要：Diagrammatic Monte Carlo (DiagMC) method is to stochastically sample the abstract configuration space in terms of perturbative Feynman diagrammatic series. While leading to an exponential growth of computational complexity as diagram order, the fermion sign is also responsible for the convergence of the perturbative diagrammatic series for many quantum systems. DiagMC can be directly applied to the thermodynamic limit—i.e., infinite system size, and moreover, take the advantage of well-known field-theoretical techniques to run the calculation in a self-consistent mode. In this talk, I shall describe the basic formulation of DiagMC, and then discuss two applications. We study the two-dimensional fermionic Hubbard model, provide finite-temperature results and obtain the ground-state phase diagram for superfluids of different symmetries for a significant range of interaction strength and doping fraction. We also find “fingerprint” evidence of the thermal spin-ice state for the quantum Heisenberg antiferromagnet on the pyrochlore lattice—a frustrated system.

Refs. EPL110 57001 (2015), PRX5 041041 (2016), PRL116 177203 (2016).