Repulsively bound pairs of particles in a lattice governed by the Bose-Hubbard model can form stable incompressible clusters of dimers corresponding to finite-size $n=2$ Mott insulators. Here we study the dynamics of hole defects in such clusters corresponding to unpaired particles which can resonantly tunnel out of the cluster into the lattice vacuum. Due to bosonic statistics, the unpaired particles have different effective mass inside and outside the cluster, and ``evaporation'' of hole defects from the cluster boundaries is possible only when their quasimomenta are within a certain transmission range. We show that quasithermalization of hole defects occurs in the presence of catalyzing particle defects which thereby purify the Mott-insulating clusters. We study the dynamics of a one-dimensional system using analytical techniques and numerically exact time-dependent density-matix renormalization-group simulations. We derive an effective strong-interaction model that enables simulations of the system dynamics for much longer times. We also discuss a more general case of two bosonic species which reduces to the fermionic Hubbard model in the strong interaction limit.Repulsively bound pairs of particles in a lattice governed by the Bose-Hubbard model can form stable incompressible clusters of dimers corresponding to finite-size $n=2$ Mott insulators. Here we study the dynamics of hole defects in such clusters corresponding to unpaired particles which can resonantly tunnel out of the cluster into the lattice vacuum. Due to bosonic statistics, the unpaired particles have different effective mass inside and outside the cluster, and ``evaporation'' of hole defects from the cluster boundaries is possible only when their quasimomenta are within a certain transmission range. We show that quasithermalization of hole defects occurs in the presence of catalyzing particle defects which thereby purify the Mott-insulating clusters. We study the dynamics of a one-dimensional system using analytical techniques and numerically exact time-dependent density-matix renormalization-group simulations. We derive an effective strong-interaction model that enables simulations of the system dynamics for much longer times. We also discuss a more general case of two bosonic species which reduces to the fermionic Hubbard model in the strong interaction limit.

arXiv:1111.1108Physical Review AJan 10, 201222 citations

Phase Coherence of an Atomic Mott Insulator

Fabrice Gerbier, Artur Widera, Simon Fölling +3 more

We investigate the phase coherence properties of ultracold Bose gases in optical lattices, with special emphasis on the Mott insulating phase. We show that phase coherence on short length scales persists even deep in the insulating phase, preserving a finite visibility of the interference pattern observed after free expansion. This behavior can be attributed to a coherent admixture of particle-hole pairs to the perfect Mott state for small but finite tunneling. In addition, small but reproducible kinks are seen in the visibility, in a broad range of atom numbers. We interpret them as signatures for density redistribution in the shell structure of the trapped Mott insulator.We investigate the phase coherence properties of ultracold Bose gases in optical lattices, with special emphasis on the Mott insulating phase. We show that phase coherence on short length scales persists even deep in the insulating phase, preserving a finite visibility of the interference pattern observed after free expansion. This behavior can be attributed to a coherent admixture of particle-hole pairs to the perfect Mott state for small but finite tunneling. In addition, small but reproducible kinks are seen in the visibility, in a broad range of atom numbers. We interpret them as signatures for density redistribution in the shell structure of the trapped Mott insulator.

arXiv:cond-mat/0503452Physical Review LettersJul 28, 2005187 citations

Dynamics of Quantum Coherence in the Jaynes-Cummings Model with Quenched Disorder

O. P. de Sá Neto, J.H. Warnes, F. M. de Paula +1 more

Jan 1, 20220 citations

Effects of Particle-Hole Asymmetry on the Mott-Hubbard Metal-Insulator Transition

D. O. Demchenko

Bulletin of the American Physical SocietyMar 23, 20050 citations

Repulsively bound pairs of particles in a lattice governed by the Bose-Hubbard model can form stable incompressible clusters of dimers corresponding to finite-size

n=2

Mott insulators. Here we study the dynamics of hole defects in such clusters corresponding to unpaired particles which can resonantly tunnel out of the cluster into the lattice vacuum. Due to bosonic statistics, the unpaired particles have different effective mass inside and outside the cluster, and ``evaporation'' of hole defects from the cluster boundaries is possible only when their quasimomenta are within a certain transmission range. We show that quasithermalization of hole defects occurs in the presence of catalyzing particle defects which thereby purify the Mott-insulating clusters. We study the dynamics of a one-dimensional system using analytical techniques and numerically exact time-dependent density-matix renormalization-group simulations. We derive an effective strong-interaction model that enables simulations of the system dynamics for much longer times. We also discuss a more general case of two bosonic species which reduces to the fermionic Hubbard model in the strong interaction limit.