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On the Sign Problem in the Hirsch-Fye Algorithm for Impurity Problems

Jaebeom Yoo·Shailesh Chandrasekharan·Ribhu K. Kaul·Denis Ullmo·Harold U. Baranger
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Abstract

We show that there is no fermion sign problem in the Hirsch and Fye algorithm for the single-impurity Anderson model. Beyond the particle-hole symmetric case for which a simple proof exists, this has been known only empirically. Here we prove the nonexistence of a sign problem for the general case by showing that each spin trace for a given Ising configuration is separately positive. We further use this insight to analyze under what conditions orbitally degenerate Anderson models or the two-impurity Anderson model develop a sign.

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Jaebeom Yoo, Shailesh Chandrasekharan, Ribhu K. Kaul, Denis Ullmo, Harold U. Baranger. 2005-11-16. On the Sign Problem in the Hirsch-Fye Algorithm for Impurity Problems. https://doi.org/10.1088/0305-4470%2F38%2F48%2F004

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