Department of Physics, University of Illinois at Urbana-Champaign, 1110 West Green Street, Urbana, Illinois 61801, USA.
Phys Rev Lett. 2012 Jul 13;109(2):025301. doi: 10.1103/PhysRevLett.109.025301. Epub 2012 Jul 9.
We study the stability of Bose condensates with Rashba-Dresselhaus spin-orbit coupling in three dimensions against quantum and thermal fluctuations. The ground state depletion of the plane-wave condensate due to quantum fluctuations is, as we show, finite, and therefore the condensate is stable. We also calculate the corresponding shift of the ground state energy. Although the system cannot condense in the absence of interparticle interactions, by estimating the number of excited particles we show that interactions stabilize the condensate even at nonzero temperature. Unlike in the usual Bose gas, the normal phase is not kinematically forbidden at any temperature; calculating the free energy of the normal phase at finite temperature, and comparing with the free energy of the condensed state, we infer that generally the system is condensed at zero temperature, and undergoes a transition to normal at nonzero temperature.
我们研究了三维中具有 Rashba-Dresselhaus 自旋轨道耦合的玻色凝聚体对量子和热涨落的稳定性。正如我们所展示的，由于量子涨落，平面波凝聚体的基态耗尽是有限的，因此凝聚体是稳定的。我们还计算了相应的基态能量移动。尽管在没有粒子间相互作用的情况下系统不能凝聚，但通过估计激发粒子的数量，我们表明相互作用甚至在非零温度下也能稳定凝聚体。与通常的玻色气体不同，在任何温度下正常相都不是动力学禁止的；在有限温度下计算正常相的自由能，并与凝聚态的自由能进行比较，我们推断一般情况下系统在零温度下凝聚，并在非零温度下转变为正常相。
