TY - JOUR

T1 - Revival of quantum correlations without system-environment back-action

AU - Compagno, Giuseppe

AU - Lo Franco, Rosario

AU - Bellomo, Bruno

AU - Andersson, Erika

AU - Lo Franco, Rosario

PY - 2012

Y1 - 2012

N2 - Revivals of quantum correlations have often been explained in terms of back-action on quantum systems by their quantum environment(s). Here we consider a system of two independently evolving qubits, each locally interacting with a classical random external field. The environments of the qubits are also independent, and there is no back-action on the qubits. Nevertheless, entanglement, quantum discord, and classical correlations between the two qubits may revive in this model. We explain the revivals in terms of correlations in a classical-quantum state of the environments and the qubits. Although classical states cannot store entanglement on their own, they can play a role in storing and reviving entanglement. It is important to know how the absence of back-action, or modeling an environment as classical, affects the kind of system time evolutions one is able to describe. We find a class of global time evolutions where back-action is absent and for which there is no loss of generality in modeling the environment as classical. Finally, we show that the revivals can be connected with the increase of a parameter used to quantify non-Markovianity of the single-qubit dynamics.

AB - Revivals of quantum correlations have often been explained in terms of back-action on quantum systems by their quantum environment(s). Here we consider a system of two independently evolving qubits, each locally interacting with a classical random external field. The environments of the qubits are also independent, and there is no back-action on the qubits. Nevertheless, entanglement, quantum discord, and classical correlations between the two qubits may revive in this model. We explain the revivals in terms of correlations in a classical-quantum state of the environments and the qubits. Although classical states cannot store entanglement on their own, they can play a role in storing and reviving entanglement. It is important to know how the absence of back-action, or modeling an environment as classical, affects the kind of system time evolutions one is able to describe. We find a class of global time evolutions where back-action is absent and for which there is no loss of generality in modeling the environment as classical. Finally, we show that the revivals can be connected with the increase of a parameter used to quantify non-Markovianity of the single-qubit dynamics.

KW - Entanglement

KW - Open quantum systems

KW - quantum correlations

KW - Entanglement

KW - Open quantum systems

KW - quantum correlations

UR - http://hdl.handle.net/10447/66643

UR - http://pra.aps.org/abstract/PRA/v85/i3/e032318

M3 - Article

VL - 85

SP - 032318-1-032318-8

JO - PHYSICAL REVIEW A

JF - PHYSICAL REVIEW A

SN - 1050-2947

ER -