Towers of quantum many-body scars under stochastic resetting

TL;DR

This paper demonstrates that stochastic resetting can be used to prepare local properties of quantum many-body scar states, damping oscillations and creating long-range order, offering a new experimental approach.

Contribution

The authors introduce a stochastic resetting protocol to prepare local properties of scarred eigenstates in quantum many-body systems, providing analytical insights and potential experimental applications.

Findings

Resetting damps scarred oscillations.

Stationary states exhibit long-range order.

States are locally equivalent to pure scarred eigenstates.

Abstract

Towers of quantum many-body scars are sets of highly-excited eigenstates of nonintegrable Hamiltonians whose dynamics shows athermal behavior and persistent oscillations in time. The preparation of such states is, however, challenging due to their entanglement content. In this work, we show that local properties of such states can be prepared by interspersing the scarred dynamics with stochastic resets to much simpler unentangled product states. Stochastic resetting amounts to reinitializing the many-body wavefunction of the system at random times to a predefined state, which we choose to be in the scarred subspace. We derive several analytical results for the ensuing dynamics, e.g., for the time evolution of the fidelity and of local observables. Resetting damps the scarred oscillations and generates spatial off-diagonal long-range order in the ensuing stationary state. The latter shows mixedness that scales logarithmically as a function of the system size, which follows from the structure of the scarred eigenstates. We prove that such stationary states are locally equivalent, in the sparse-resetting limit, to a single pure scarred eigenstate, which is determined by the reset state. This protocol thereby might represent a route to the experimental preparation of the local properties of correlated and entangled states through resetting.