Constraints from anti-unitary symmetries on phase diagrams of sign problem-free models

Xu Zhang; Nick Bultinck

doi:10.1103/pxsx-33qy

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arXiv · 2503.07747

Constraints from anti-unitary symmetries on phase diagrams of sign problem-free models

Xu Zhang·Nick Bultinck

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Abstract

A powerful way to guarantee the absence of a sign problem in determinantal quantum Monte Carlo simulations is imposing a particular type of anti-unitary symmetries. It is shown that these same symmetries give rise to constraints on correlation functions, which can be used to identify local operators whose correlations upper bound those of a large class of physically relevant operators, including for example superconducting order parameters. Our results also help understand why it is difficult to realize generic finite-momentum orders in sign problem-free models.

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Xu Zhang, Nick Bultinck. 2025-03-10. Constraints from anti-unitary symmetries on phase diagrams of sign problem-free models. https://doi.org/10.1103/pxsx-33qy

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