Quantifying fermionic decoherence in many-particle systems

Andrea Valdés-Hernández, A. P. Majtey, Angel Ricardo Plastino

Information that is stored in quantum-mechanical systems can be easily lost because of the interaction with the environment in a process known as decoherence. Possible physical implementations of many processes in quantum information theory involve systems of identical particles, whence comprehension of the dynamics of entanglement induced by decoherence processes in identical-particle open systems becomes relevant. Here we study the effects and concomitant entanglement evolution arising from the interaction between a system of two identical fermions and the environment for two paradigmatic quantum channels. Entanglement measures are introduced to quantify the entanglement between the different parties, and a study of the dynamics of entanglement for some particular examples is carried out. Our analysis, which includes also the evolution of an entanglement indicator based on an entropic criteria, offers insights into the dynamics of entanglement in open systems of identical particles, involving the emergence of multipartite genuine entanglement. The results improve our understanding of the phenomenon of decoherence and will provide strategies to control it.

Philip L. Bowers

W. D. Kraeft, D. Kremp, W. Ebeling +1 more

Bussandri, Diego, Majtey, Ana Paula, Valdés Hernández, Andrea

We analyze the dynamics of entanglement due to decoherence in asystem of two identical fermions with spin 3/2 interacting with a global bosonicenvironment. We make use of an appropriate measure of the so-called fermionicentanglement to quantify the fermionic correlations, and compare the dynamicaleffects due to decoherence with those that arise in a pair of distinguishablequbits immersed in the same environment. According to the system?s initialstate, three types of qualitatively different dynamics are identified: i) invariantregime, corresponding to initial states that belong to a decoherence free subspace(DFS), which maintain invariant their entanglement and coherence throughoutthe evolution; ii) exponential decay, corresponding to initial states orthogonal tothe DFS, and evolve towards states whose entanglement and coherence decreaseexponentially; iii) entanglement sudden death, corresponding to initial states that havesome overlap with the DFS and exhibit a richer dynamics leading, in particular,to the sudden death of the fermionic entanglement, while the coherence decaysexponentially. Our analysis offers insights into the dynamics of entanglementin open systems of identical particles and into the existence of decoherence freesubspaces and entanglement sudden death in indistinguishable-fermion systems.

Hans A. De Raedt, V. V. Dobrovitski

D G Bussandri, A P Majtey, A Valdés-Hernández

Abstract 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 make use of an appropriate measure of the so-called fermionic entanglement to quantify the fermionic correlations, and compare the dynamical effects due to decoherence with those that arise in 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) 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) exponential decay , corresponding to initial states orthogonal to the DFS, and evolve towards states whose entanglement and coherence decrease exponentially; iii) 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 and into the existence of decoherence free subspaces and entanglement sudden death in indistinguishable-fermion systems.