Decoherence of Bell states by local interactions with a dynamic spin environment

Abstract

We study the evolution of a system of two qubits, each of which interacts locally with a spin chain with nontrivial internal Hamiltonian. We present an exact solution to this problem and analyze the dependence of decoherence on the distance between the interaction sites. In the strong coupling regime we find that decoherence increases with increasing distance. In the weak coupling regime the dependence of decoherence with distance is not generic (i.e., it varies according to the initial state). Decoherence becomes independent of distance when the latter is over a saturation length $l$. Numerical results for the Ising chain suggest that the saturation scale is related to the correlation length $\xi$. For strong coupling we display evidence of the existence of non--Markovian effects (such as environment--induced interactions between the qubits). As a consequence the system can undergo a quasiperiodic sequence of ``sudden deaths and revivals'' of entanglement, with a time scale related to the distance between qubits.

Replaced with published version (minor changes). 8 pages, 7 figures. Continues work of arXiv:0709.2643

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• Open-System Dynamics of Entanglement
• Non-Markovianity, Loschmidt echo and criticality: a unified picture
• Delayed sudden death of entanglement at exceptional points
• Finite-time destruction of entanglement and non-locality by environmental influences
• Decoherence effects in interacting qubits under the influence of various environments
• Experimental investigation of enviroment--induced entanglement using an all--optical setup
• Entanglement dynamics of two-bipartite system under the influence of dissipative environments
• Manipulating and protecting entanglement by means of spin environments
• Probing the out-of-equilibrium dynamics of two interacting atoms
• Dynamics of decoherence of an entangled pair of qubits locally connected to a one-dimensional disordered spin chain
• Generation of concurrence between two qubits locally coupled to a one dimensional spin chain
• Decoherence of Bell states by local interactions with a suddenly quenched spin environment
• QBism, FAPP and the Quantum Omelette. (Or, Unscrambling Ontological Problems from Epistemological Solutions in QM)
• Acute entanglement and Photon/Phonons statistics in a balanced/unbalanced PT-symmetry systems