Critical exponents of the superfluid-Bose-glass transition in three dimensions

• Published in: Physical review letters Vol. 112; no. 22; p. 225301
• Main Authors: Yao, Zhiyuan, da Costa, Karine P C, Kiselev, Mikhail, Prokof'ev, Nikolay
• Format: Journal Article
• Language: English
• Published: United States 03.06.2014
• ISSN: 1079-7114
• DOI: 10.1103/physrevlett.112.225301

Recent experimental and numerical studies of the critical-temperature exponent ϕ for the superfluid-Bose-glass universality in three-dimensional systems report strong violations of the key quantum critical relation, ϕ=νz, where z and ν are the dynamic and correlation-length exponents, respectively; these studies question the conventional scaling laws for this quantum critical point. Using Monte Carlo simulations of the disordered Bose-Hubbard model, we demonstrate that previous work on the superfluid-to-normal-fluid transition-temperature dependence on the chemical potential (or the magnetic field, in spin systems), T_{c}∝(μ-μ_{c})^{ϕ}, was misinterpreting transient behavior on approach to the fluctuation region with the genuine critical law. When the model parameters are modified to have a broad quantum critical region, simulations of both quantum and classical models reveal that the ϕ=νz law [with ϕ=2.7(2), z=3, and ν=0.88(5)] holds true, resolving the ϕ-exponent "crisis."