Sudden death of entanglement in fermionic systems under collective decoherence

• Main Authors: Bussandri, D. G, Majtey, A. P, Valdés-Hernández, A
• Format: Journal Article
• Language: English
• Published: 19-08-2020
• Subjects: Physics - Quantum Physics
• DOI: 10.48550/arxiv.2008.08545

We analyze the dynamics of entanglement due to decoherence in a system of two
identical fermions with spin $3/2$ interacting with a global bosonic
environment. We resort to an appropriate measure of the so-called fermionic
entanglement to quantify the fermionic correlations, and compare its dynamics
with that of a pair of distinguishable qubits immersed in the same environment.
According to the system's initial state, three types of qualitatively different
dynamics are identified: i) \textit{invariant regime}, corresponding to initial
states that belong to a decoherence free subspace (DFS), which maintain
invariant their entanglement and coherence throughout the evolution; ii)
\textit{exponential decay}, corresponding to initial states orthogonal to the
DFS, and evolve towards states whose entanglement and coherence decrease
exponentially; iii) \textit{entanglement sudden death}, corresponding to
initial states that have some overlap with the DFS and exhibit a richer
dynamics leading, in particular, to the sudden death of the fermionic
entanglement, while the coherence decays exponentially. Our analysis offers
insights into the dynamics of entanglement in open systems of identical
particles, into its comparison with the distinguishable-party case, and into
the existence of decoherence free subspaces and entanglement sudden death in
indistinguishable-fermion systems.