Publications [#245112] of Harold U. Baranger

Papers Published

1. Yoo, J; Chandrasekharan, S; Kaul, RK; Ullmo, D; Baranger, HU, On the Sign Problem in the Hirsch-Fye Algorithm for Impurity Problems, J. Phys. A: Math. and General, vol. 38 no. 48 (2005), pp. 10307, cond-mat/0412771 [pdf], [doi]
   (last updated on 2026/01/16)

   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 analyse under what conditions orbitally degenerate Anderson models or the two-impurity Anderson model develop a sign. © 2005 IOP Publishing Ltd.