Sudden expansion and domain wall melting in clean and disordered optical lattices

          @misc{ pirsa_PIRSA:16050028,
            doi = {10.48660/16050028},
            url = {https://pirsa.org/16050028},
            author = {Hauschild, Johannes},
            keywords = {Condensed Matter},
            language = {en},
            title = {Sudden expansion and domain wall melting in clean and disordered optical lattices},
            publisher = {Perimeter Institute},
            year = {2016},
            month = {may},
            note = {PIRSA:16050028 see, \url{https://pirsa.org}}
          }
          

Abstract

We numerically investigate the expansion of clouds of hard-core bosons in a 2D square lattice using a matrix-product state based method. This non-equilibrium setup is induced by quenching a trapping potential to zero and is specifically motivated by an experiment with ultracold atoms [1]. As the anisotropy for hopping amplitudes in different spatial directions is varied from 1D to 2D, we observe a crossover from a fast ballistic expansion in the 1D limit to much slower dynamics in the isotropic 2D lattice [2].

 

Introducing a site-dependent disorder potential allows to study many body localization (MBL). In a very recent experiment, the melting of a domain wall gave evidence for an MBL transition in 2D [3]. We study 1D and quasi-1D models, for which the phase diagram in the presence of disorder is known, such as the Anderson insulator, Aubry-Andre model and interacting fermions in 1D and on a two-leg ladder [4]. By considering several observables, we demonstrate that the domain wall melting can indeed yield quantitative information on the transition from an ergodic to the MBL phase as a function of disorder.

 

[1] J. P. Ronzheimer et al., PRL 110, 205301 (2013) [2] J. Hauschild et al., PRA 92, 053629 (2015) [3] J. Choi et al., arXiv:1604.04178 (2016) [4] J. Hauschild et al., in preparation