# Dynamical quantum phase transitions in collapse and revival oscillations of a quenched superfluid

## TL;DR

This paper demonstrates that collapse and revival oscillations in a quenched superfluid are governed by a sequence of dynamical quantum phase transitions, revealing their inherent nonequilibrium quantum many-body nature.

## Contribution

It identifies the role of dynamical quantum phase transitions in controlling collapse and revival oscillations in a quenched superfluid, highlighting their nonequilibrium origin.

## Key findings

- Oscillation time scale linked to dynamical quantum phase transitions
- Oscillations depend on initial conditions and final Hamiltonian
- Revealed nonanalyticities in Loschmidt echos as signatures

## Abstract

In this work we revisit collapse and revival oscillations in superfluids suddenly quenched by strong local interactions for the case of a one-dimensional Bose-Hubbard model. As the main result we identify the inherent nonequilibrium quantum many-body character of these oscillations by revealing that they are controlled by a sequence of underlying dynamical quantum phase transitions in the real-time evolution after the quench, which manifest as temporal nonanalyticities in return probabilities or Loschmidt echos. Specifically, we find that the time scale of the collapse and revival oscillations is, firstly, set by the frequency at which dynamical quantum phase transitions appear, and is, secondly, of emergent nonequilibrium nature, since it is not only determined by the final Hamiltonian but also depends on the initial condition.