Chiral Bloch-Zener Oscillations Of Spin-Orbit Coupled Cold Atoms In An Optical Superlattice

The experimental realization of Bose-Einstein condensations opens up the exploration of macroscopic quantum effects in ultracold atomic gases.In condensed matter physics,it’s very difficult to accurately investigate the dynamics of particles and the effect of every interactions because of the existence of various interactions.When ultracold atoms are loaded into optical lattices,the highly purity and controllability make this system become an ideal platform to perform the quantum simulation,which includes the investigation of the dynamics of particles and novel quantum effects in lattice potentials.Based on these,neutral ultracold atoms can also be used to simulate the dynamics of charged particles in electromagnetic fields by applying the effect of spin-orbit coupling.These distinctive advantages motivate us to conduct extensive research on cold atomic systems.In this paper,we mainly study the chiral Bloch oscillation and chiral Bloch-Zener oscillation dynamics of spin-orbit coupled cold atoms in an optical superlattice.We exhibit the theoretical model of our system and map the Hamiltonian into a tilted twoleg ladder pierced by an effective magnetic flux.By calculating Wannier-Stark states,we investigate chiral Bloch oscillation dynamics.Within unchanged spin-orbit coupling parameters,the chiral Bloch-Zener oscillations can be induced by adjusting the optical lattice parameter,the corresponding Landau-Zener tunneling probability can be analytically derived by the Landau-Zener model and the result is in agreement with the numerical simulation.Finally,we discuss the quantum transition in the system and it can be characterized by the discontinuity of the first derivative of spin polarizations and chiral currents.It’s noteworthy that the chiral Bloch-Zener oscillation dynamics still exhibit potential application prospects of spin-dependent interferometers.