Krutitsky K V, Graham R
Fachbereich Physik der Universität Duisburg-Essen, Standort Essen, Universitätsstrasse 5, Postfach 10 37 64, 45117 Essen, Germany.
Phys Rev Lett. 2003 Dec 12;91(24):240406. doi: 10.1103/PhysRevLett.91.240406. Epub 2003 Dec 11.
The superfluid-Mott insulator phase transition in a Bose-Einstein condensate of neutral atoms with doubly degenerate internal ground states in an optical lattice is theoretically investigated. The optical lattice is created by two counterpropagating linearly polarized laser beams with the angle theta between the polarization vectors (lin-angle-lin configuration). The phase diagram of the system and the critical values of the parameters are worked out. It is shown that the sign of the detuning plays an important role and that there is a strong suppression of the Mott transition in the case of blue detuning. Varying the laser intensity and/or the angle theta one can manipulate the Mott insulator to superfluid quantum phase transition as well as prepare the condensate in physically distinguishable "ferromagnetic" and "antiferromagnetic" superfluid states.
对处于光学晶格中具有双重简并内部基态的中性原子玻色 - 爱因斯坦凝聚体中的超流体 - 莫特绝缘体相变进行了理论研究。光学晶格由两束反向传播的线偏振激光束产生，其偏振矢量之间的夹角为θ（线 - 角 - 线构型）。计算出了系统的相图和参数的临界值。结果表明，失谐的符号起着重要作用，并且在蓝失谐情况下莫特相变受到强烈抑制。通过改变激光强度和/或角度θ，可以操控莫特绝缘体到超流体的量子相变，以及制备处于物理上可区分的“铁磁”和“反铁磁”超流体状态的凝聚体。
