Cavity-assisted Bloch Oscillation Of Cold Atoms In A One-Dimensional Quasiperiodic Optical Lattice

Optical lattice combined with cold atoms provides abundant quantum phenomena for atomic physics.It is a quite clear system in which the lattice constant can be adjusted by changing the wave length of coherent light beams and the depth of potential wells can be modulated by changing the intensity of coherent light beams.The feedback between atoms and optical cavity makes it possible to perform non-destructive detection.Therefore,it can be used to observe some physical phenomena which are difficult to detect in other systems;At the same time,it provides an effective method for precision measurement.The mode is constituted by a non-interacting Bose-Einstein condensate contained in a Fabry-Perot optical resonator.Two incommensurate standing-wave modes are excited in the resonator thus forming a quasiperiodic optical potential for the atoms.One mode is main lattice which is relatively strong and independent on atomic dynamics;The other mode is vice-lattice which is raletively weak and affected by atomic dynamics.Constant external force is provided by the gravitational force of the atoms?By numerical simulation,we solve the coupled equations of motion for the light and atomic field to derive the dynamics.The main methods we use in dealing with the equations are: split operators and Bloch waves technique.Cold atoms do periodic oscillation in optical lattice with constant period in coordinate space and momentum space when constant external force is exerted on them,and the period of oscillation is Bloch period which is modulated by external force and lattice constant.Also,the cavity mode is adjusted by Bloch period as well.While in quasi-periodic lattice,the periodicity of oscillation will be disturbed in both coordinate space and momentum space.The disruption is related with lattice constants.The relationship between transmission light and the intra-cavity potential makes it possible to obtain the information of the system by detecting the transmission only which means there is no destruction to the information of the system thus providing a new idea and method for precision measurement;the property of quasiperiodic lattice also lays the foundation for the study of imperfect lattice and nonlinear optics.