SciPost Phys. 1, 010 (2016) ·
published 27 October 2016

· pdf
The manybody localization (MBL) transition is a quantum phase transition
involving highly excited eigenstates of a disordered quantum manybody
Hamiltonian, which evolve from "extended/ergodic" (exhibiting extensive
entanglement entropies and fluctuations) to "localized" (exhibiting arealaw
scaling of entanglement and fluctuations). The MBL transition can be driven by
the strength of disorder in a given spectral range, or by the energy density at
fixed disorder  if the system possesses a manybody mobility edge. Here we
propose to explore the latter mechanism by using "quantumquench spectroscopy",
namely via quantum quenches of variable width which prepare the state of the
system in a superposition of eigenstates of the Hamiltonian within a
controllable spectral region. Studying numerically a chain of interacting
spinless fermions in a quasiperiodic potential, we argue that this system has
a manybody mobility edge; and we show that its existence translates into a
clear dynamical transition in the time evolution immediately following a quench
in the strength of the quasiperiodic potential, as well as a transition in the
scaling properties of the quasistationary state at long times. Our results
suggest a practical scheme for the experimental observation of manybody
mobility edges using coldatom setups.