Finite-temperature phase transitions in a two-dimensional boson Hubbard model.
Finite-temperature phase transitions in a two-dimensional boson Hubbard model.
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DOI：
10.1103/physrevlett.98.266406
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发表时间：
2007-04
影响因子：
8.6
通讯作者：
Min-Chul Cha;Ji-Woo Lee
中科院分区：
文献类型：
--
作者：
Min-Chul Cha;Ji-Woo Lee
通过对量子转子模型的蒙特卡罗模拟，研究了具有零点量子涨落的二维玻色子Hubbard模型的有限温度相变，并构造了相应的相图。可压缩性在绝缘状态下表现为热激活的间隙行为。超流体刚度的有限尺度清晰地显示了Kosterlitz-Thouless跃迁的性质。转变温度T(c)证实了T(c)成比例的缩放关系，rho(0)(x), x=1.0。给出了低温下反常量子行为的一些证据。
We study finite-temperature phase transitions in a two-dimensional boson Hubbard model with zero-point quantum fluctuations via Monte Carlo simulations of a quantum rotor model and construct the corresponding phase diagram. Compressibility shows a thermally activated gapped behavior in the insulating regime. Finite-size scaling of the superfluid stiffness clearly shows the nature of the Kosterlitz-Thouless transition. The transition temperature T(c) confirms a scaling relation T(c) proportional, rho(0)(x), with x=1.0. Some evidence of anomalous quantum behavior at low temperatures is presented.