Quantum Monte Carlo simulations of antiferromagnetism in ultracold fermions on optical lattices within real-space dynamical mean-field theory

摘要

We present a massively parallel quantum Monte Carlo based implementation ofreal-space dynamical mean-field theory for general inhomogeneous correlatedfermionic lattice systems. As a first application, we study magnetic order in abinary mixture of repulsively interacting fermionic atoms harmonically trappedin an optical lattice. We explore temperature effects and establish signaturesof the N\'{e}el transition in observables directly accessible in cold-atomexperiments; entropy estimates are also provided. We demonstrate that the localdensity approximation (LDA) fails for ordered phases. In contrast, a "slab"approximation allows us to reach experimental system sizes with O(10^5) atomswithout significant loss of accuracy.