Orbifold Equivalence and the Sign Problem at Finite Baryon Density

Aleksey Cherman, Masanori Hanada, and Daniel Robles-Llana

Phys. Rev. Lett. 106, 091603 – Published 3 March 2011

Abstract

We point out that $S O (2 N_{c})$ gauge theory with $N_{f}$ fundamental Dirac fermions does not have a sign problem at finite baryon number chemical potential $μ_{B}$ . One can thus use lattice Monte Carlo simulations to study this theory at finite density. The absence of a sign problem in the $S O (2 N_{c})$ theory is particularly interesting because a wide class of observables in the $S O (2 N_{c})$ theory coincide with observables in QCD in the large $N_{c}$ limit, as we show using the technique of large $N_{c}$ orbifold equivalence. We argue that the orbifold equivalence between the two theories continues to hold at finite $μ_{B}$ provided one adds appropriate deformation terms to the $S O (2 N_{c})$ theory. This opens up the prospect of learning about QCD at finite $μ_{B}$ using lattice studies of the $S O (2 N_{c})$ theory.

Received 21 October 2010

DOI:https://doi.org/10.1103/PhysRevLett.106.091603

Authors & Affiliations

Aleksey Cherman^1,*, Masanori Hanada^2,†, and Daniel Robles-Llana^2,‡

¹Maryland Center for Fundamental Physics, Department of Physics, University of Maryland, College Park, Maryland 20742-4111, USA
²Department of Particle Physics and Astrophysics, Weizmann Institute of Science, Rehovot 76100, Israel

^*Present address: DAMTP, University of Cambridge, Cambridge CB3 0WA, U.K. a.cherman@damtp.cam.ac.uk
^†Present address: Department of Physics, University of Washington, Seattle, WA 98195-1560, USA. mhanada@u.washington.edu
^‡daniel.robles@weizmann.ac.il