Journal of Experimental and Theoretical Physics
A new quantum Monte Carlo algorithm in the momentum representation: The sign problem and the Hess-Fairbank effect
Petr F. Kartsev
Abstract
An exact numerical algorithm based on the diagrammatic quantum Monte Carlo method in the momentum representation is proposed; in many cases, this algorithm is free of the sign problem and extends the class of models that can be analyzed by cluster methods. The weakening of the sign problem is demonstrated via the determination of the ground state of electrons on a chain in the Hubbard model. The algorithm is applied to the investigation of the behavior of a one-dimensional boson system with attraction in a rotating ring in the region of the Hess-Fairbank effect predicted by Ueda and Leggett. The existence of this effect for a comparatively small number of particles N ∼ 10 is confirmed. An analytic boundary of this effect is determined in the limit as N → ∞.