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, Journal of Physics A: Mathematical and General, vol. 38 no. 48 (2005), pp. 10307-10310, cond-mat/0412771 [pdf], [doi] .

    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.