Decoherence-free subspaces and Markovian revival of genuine multipartite entanglement in a dissipative system

TL;DR

This paper studies how genuine multipartite entanglement in a multi-qubit system can persist and revive due to decoherence-free subspaces and interference effects, even in dissipative environments.

Contribution

It reveals the role of symmetry-induced structures and decoherence-free subspaces in protecting and reviving multipartite entanglement in open quantum systems.

Findings

Genuine multipartite entanglement can revive in Markovian regimes due to interference effects.

Decoherence-free subradiant subspaces protect parts of the state from dissipation.

Parameter regimes are identified where entanglement revival occurs.

Abstract

We investigate the dynamics of genuine multipartite entanglement (GME) in a system of $n$ qubits ($n\ge3$) collectively interacting with a common zero temperature bosonic bath characterized by a Lorentzian spectral density. Restricting the dynamics to the single excitation sector, the collective system-bath coupling naturally separates the Hilbert space into a superradiant mode and a subspace of states orthogonal to it, which forms a decoherence free (subradiant) subspace. We show that this symmetry induced structure leads to persistent components of the state that remain protected from dissipation. Specifically, in the three qubit case, the time evolution of genuine tripartite entanglement is analyzed using the convex roof extension of negativity. We identify parameter regimes determined by the bath spectral density and collective coupling strengths that correspond to Markovian and non-Markovian dynamics. In the Markovian limit, we demonstrate that GME can exhibit a nontrivial revival even in the absence of environmental memory effects. This revival arises from the destructive interference between the decaying superradiant component and the invariant subradiant subspace under suitable system configuration, leading to a transient loss of GME.