Localization and Glassy Dynamics Of Many-Body Quantum Systems

TLDR

Classical and quantum systems can become trapped in limited regions of configuration or Hilbert space, leading to aging, glass formation, and non‑ergodic behavior. The study proposes to experimentally probe out‑of‑equilibrium dynamics of prepared cold‑atom quantum states to uncover this rich phenomenology. The authors attribute the phenomenon to a threshold‑energy‑induced slowdown of incoherent density excitations, akin to dynamical arrest at a glass transition. Numerical simulations show that far‑from‑equilibrium lattice bosons become trapped in long‑lived inhomogeneous metastable states, explaining the observed lack of thermalization in large systems.

Abstract

When classical systems fail to explore their entire configurational space, intriguing macroscopic phenomena like aging and glass formation may emerge. Also closed quanto-mechanical systems may stop wandering freely around the whole Hilbert space, even if they are initially prepared into a macroscopically large combination of eigenstates. Here, we report numerical evidences that the dynamics of strongly interacting lattice bosons driven sufficiently far from equilibrium can be trapped into extremely long-lived inhomogeneous metastable states. The slowing down of incoherent density excitations above a threshold energy, much reminiscent of a dynamical arrest on the verge of a glass transition, is identified as the key feature of this phenomenon. We argue that the resulting long-lived inhomogeneities are responsible for the lack of thermalization observed in large systems. Such a rich phenomenology could be experimentally uncovered upon probing the out-of-equilibrium dynamics of conveniently prepared quantum states of trapped cold atoms which we hereby suggest.