Effect of non-Markovianity on the dynamics of coherence, concurrence and Fisher information

Samyadeb Bhattacharya, Subhashish Banerjee, Arun Kumar Pati

Published 2016-01-15Version 1

A master equation has been constructed for a global system-bath interaction both in the absence as well as presence of non-Markovian noise. The master equation has been exactly solved for a special class of two qubit X states (which contains Bell diagonal and Werner states). The $l_1$ norm of coherence has been calculated to observe the dynamics of quantum coherence in the presence of a global system-bath interaction. We show that the global part of the system-bath interaction compensates for the decoherence, resulting in the slow down of coherence decay. The concurrence and the Fisher information, explicitly calculated for a particular two qubit Werner state, indicate that the decay of these quantum features also slow down under a global system-bath interaction. We also show that the coherence is the most robust of all the three non-classical features under environmental interaction. Entanglement is shown to be the most costly of them all. For an appropriately defined limiting case, all the three quantities show freezing behaviour. This limiting condition is attainable when the separations between the energy levels of both the atomic qubits are small.