Larson Jonas, Damski Bogdan, Morigi Giovanna, Lewenstein Maciej
ICFO-Institut de Ciències Fotòniques, E-08860 Castelldefels, Barcelona, Spain.
Phys Rev Lett. 2008 Feb 8;100(5):050401. doi: 10.1103/PhysRevLett.100.050401. Epub 2008 Feb 4.
We study the low temperature physics of an ultracold atomic gas in the potential formed inside a pumped optical resonator. Here, the height of the cavity potential, and hence the quantum state of the gas, depends not only on the pump parameters, but also on the atomic density through a dynamical ac-Stark shift of the cavity resonance. We derive the Bose-Hubbard model in one dimension and use the strong coupling expansion to determine the parameter regime in which the system is in the Mott-insulator state. We predict the existence of overlapping, competing Mott-insulator states, and bistable behavior in the vicinity of the shifted cavity resonance, controlled by the pump parameters. Outside these parameter regions, the state of the system is in most cases superfluid.
我们研究了在泵浦光学谐振腔内形成的势场中极冷原子气体的低温物理。在此，腔势的高度，进而气体的量子态，不仅取决于泵浦参数，还通过腔共振的动态交流斯塔克位移取决于原子密度。我们推导了一维的玻色 - 哈伯德模型，并使用强耦合展开来确定系统处于莫特绝缘态的参数区域。我们预测了重叠、竞争的莫特绝缘态的存在，以及在由泵浦参数控制的腔共振位移附近的双稳行为。在这些参数区域之外，系统的状态在大多数情况下是超流态。
