Double occupancy as a universal probe for antiferromagnetic correlations and entropy in cold fermions on optical lattices

E. V. Gorelik; T. Paiva; R. Scalettar; A. Klümper; N. Blümer

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arXiv · 1105.3356

Double occupancy as a universal probe for antiferromagnetic correlations and entropy in cold fermions on optical lattices

E. V. Gorelik·T. Paiva·R. Scalettar·A. Klümper·N. Blümer

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Abstract

We verify signatures of antiferromagnetic (AF) correlations in the double occupancy D [Gorelik et al., PRL 105, 065301 (2010)] and study their dimensional dependence using direct quantum Monte Carlo in dimensions d=2,3 and Bethe Ansatz in d=1. We find quantitative agreement with dynamical mean-field theory (DMFT) in the cubic case and qualitative agreement down to d=1. As a function of entropy s=S/(N k_B), D is nearly universal with respect to d; the minimum in D(s) approaches s=log(2) at strong coupling, as predicted by DMFT. Long-range order appears hardly relevant for the current search of AF signatures in cold fermions. Thus, experimentalists need not achieve s<log(2)/2 and should consider lower dimensions, for which the AF effects are larger.

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E. V. Gorelik, T. Paiva, R. Scalettar, A. Klümper, N. Blümer. 2011-05-17. Double occupancy as a universal probe for antiferromagnetic correlations and entropy in cold fermions on optical lattices. https://arxiv.org/abs/1105.3356

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