# CMT Theory Seminar: Dynamics of spin-1 bosons in an optical lattice: Spin mixing, quantum-phase-revival spectroscopy, and effective three-body interactions

Thursday, September 12, 2013 – 1:30pm – 3:00pm

Regents 351

Khan Mahmud

Joint Quantum Institute of UMD and NIST

In this talk we present a theoretical study of the dynamics of spin-1 atoms in an optical lattice in a quantum quench scenario where we start from a superfluid ground state in a shallow lattice potential and suddenly raise the lattice depth. The time evolution of the nonequilibrium state shows collective collapse-and-revival oscillations of matter-wave coherence as well as oscillations in the spin populations. We find that the complex pattern of these two types of oscillations reveals details about the superfluid and magnetic properties of the initial many-body ground state. Furthermore, the strengths of the spin-dependent and spin-independent atom-atom interactions can be deduced from the observations. The Hamiltonian that describes the physics of the final deep lattice not only contains two-body interactions but also effective multibody interactions, which arise due to virtual excitations to higher bands. We find that the spin-mixing dynamics contains signature of this effective three-body interactions. Spinor atoms are unique in the sense that multibody interactions are directly evident in the in situ number densities.

Host: Jim Freericks