Department of Physics, University of Massachusetts, Amherst, Massachusetts 01003, USA.
Department of Physics, University of Massachusetts, Amherst, Massachusetts 01003, USA and Instituto de Física, Universidade de São Paulo, 05508-090 São Paulo, Brazil.
Phys Rev Lett. 2014 Jun 6;112(22):225301. doi: 10.1103/PhysRevLett.112.225301. Epub 2014 Jun 3.
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."
最近对三维系统中超流-Bose 玻璃普适性的临界温度指数 ϕ 的实验和数值研究报告称，其强烈违反了关键的量子临界点关系 ϕ=νz，其中 z 和 ν 分别是动力学和相关长度指数；这些研究对该量子临界点的传统标度律提出了质疑。通过对无序玻色-哈伯德模型的蒙特卡罗模拟，我们证明了先前关于超流到正常流体转变温度对化学势（或自旋系统中的磁场）依赖关系 T_{c}∝(μ-μ_{c})^{ϕ}的研究是对接近涨落区的瞬态行为的错误解释，而真正的临界定律则不是这样。当模型参数被修改为具有更广泛的量子临界点时，量子和经典模型的模拟都表明 ϕ=νz 定律[其中 ϕ=2.7(2)，z=3，ν=0.88(5)]成立，从而解决了 ϕ 指数的“危机”。
