在冷原子物理中,对无序和温度效应的研究一直是一个非常重要的课题。基于金兹堡-朗道理论,我们从解析上研究了无序和有限温度对光晶格中超冷玻色系统相变的影响。我们的计算结果显示,无序强度的增加会使得系统的Mott绝缘相区域减小;热涨落的存在将进一步破坏Mott绝缘相,同时使得系统中出现了正常流体相。这里的金兹堡-朗道理论在最低阶近似下得到的相界方程与平均场结果一致,原则上很容易将计算结果推广到高阶从而给出超越平均场的结果。

The effects of disorder and finite temperature have been an important topic in the area of cold-atom physics. Based on the Ginzburg-Landau theory, we analytically investigated the disorder and temperature effects on the phase transition of the trapped ultra-cold Bose gases. Our calculations suggested that, with the increase of the disorder strength, the Mott-insulator lobe shrinks; the thermal fluctuations can further damage the Mott-insulator phase, and leads to the appearance of normal-fluid phase. To the lowest order of hopping parameter, the Ginzburg-Landau theory developed here gives the same phase boundary equation as mean-field theory does. It is straightforward to include higher order corrections so that the beyond mean-field results could be obtained in the near future.