Embedding Quantum Many-Body Scars into Decoherence-Free Subspaces

TL;DR

This paper introduces a framework for embedding quantum many-body scars into decoherence-free subspaces, enabling persistent oscillations and potential quantum metrology applications in open quantum systems.

Contribution

The authors develop a method to exactly embed many-body scar states into decoherence-free subspaces of Lindblad equations, facilitating controlled dissipative scar dynamics.

Findings

Persistent periodic oscillations in dissipative scarred dynamics

Construction of Liouvillian dissipators that preserve scar towers

Proposal for experimental observation using quantum simulations

Abstract

Quantum many-body scars are non-thermal excited eigenstates of non-integrable Hamiltonians, which could support coherent revival dynamics from special initial states when scars form an equally spaced tower in the energy spectrum. For open quantum systems, engineering many-body scarred dynamics by a controlled coupling to the environment remains largely unexplored. In this paper, we provide a general framework to exactly embed quantum many-body scars into the decoherence-free subspaces of Lindblad master equations. The dissipative scarred dynamics manifest persistent periodic oscillations for generic initial states, and can be practically utilized to prepare scar states with potential quantum metrology applications.We construct the Liouvillian dissipators with the local projectors that annihilate the whole scar towers, and utilize the Hamiltonian part to rotate the undesired states out of the null space of dissipators. We demonstrate our protocol through several typical models hosting many-body scar towers, and propose an experimental scheme to observe the dissipative scarred dynamics based on digital quantum simulations and resetting ancilla qubits.