Generation of coherent matter waves from correlated insulators.

Karem Rodriguez Ramirez

Universität Stuttgart

We study the evolution of matter waves resulting from the free expansion of an initially confined Mott-insulator, using a variant of the time-dependent density matrix renormalization group method (DMRG) that approximates the time-evolution operator within a Krylov subspace. A carefull comparison with the exact solution in the case of hard-core bosons (HCB) is performed, in order to determine the limitations of the algorithm. Finally, we discuss the expansion of soft-core bosons (SCB). description: The previous work carried out in the institut an exact treatment of hard-core bosons (HCB) on a 1D lattice was achieved. It was shown that a quasicoherent matter wave emerges spontaneously from a Fock state of HCB with a wavelength that can be fully controlled given the lattice parameter a. A time-dependent DMRG is implemented for the expansion of HCB and the algorithm is confronted with the exact results. And also the extension of the algorithm to SCB is currently under way, in this way, the path should be paved to reach an atom laser with tunable wavelength. The aim of my research is to stady numerically the generation of coherent matter waves by a free expansion of strongly interacting bosons on an optical lattice out of correlated insulatrs.