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

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.