Controlling Sudden Birth and Sudden Death of Entanglement at Finite Temperature

Abstract

The decoherence and the decay of quantum entanglement due to both population relaxation and thermal effects are investigated for the two qubits initially prepared in the extended Werner-like state by solving the Lindblad form of the master equation, where each qubit is interacting with an independent reservoir at finite temperature T . Entanglement sudden death (ESD) and entanglement sudden birth (ESB) are observed during the evolution process. We analyze in detail the effects of the mixedness, the degree of entanglement of the initial states and finite temperature on the time of entanglement sudden death and entanglement sudden birth. We also obtain an analytic formula for the steady state concurrence that shows its dependence on both the system parameters, the decoherence rate and finite temperature. These results arising from the combination of extended Werner-like initial state and independent thermal reservoirs suggest an approach to control the maximum possible concurrence even after the purity and finite temperature induce sudden birth, death and revival.

Steady-state entanglement of two coupled qubits

“…Another possibility, close to the one addressed in the present text, is to consider two qubits already coupled, whose entanglement builds in the steady state despite dissipation and decoherence from two independent environments [25][26][27][28][29][30][31][32][33]. Entanglement, being essentially a property that requires * Electronic address: elena.delvalle.reboul@gmail.com great purity of the state, is very sensitive to such decoherence.…”

Entanglement and Fidelity of a Spin Ladder with Dzyaloshinsky—Moriya Interaction

“…For instance, vanadyl pyrophosphate (VO) 2 P 2 O 7 , [19] strontium cuprate SrCu 2 O 3 , [20] and cupric nitrate "trihydrate" Cu(NO 3 ) 2 • (5/2)H 2 O [21] are widely investigated in condensed matter physics and quantum information science. It is important to investigate the dynamical properties for these solid state systems when they are connected to the surrounding environment, which can be treated as noisy channels, [22] i.e., amplitude damping, phase damping, and depolarizing channels.…”

Entangled Subspaces for Two Coupled Qubits in a Normal Environment

“…In addition, the application of the geometric quantum computation [13][14][15] has motivated people's interests how to implement a universal geometric quantum gate in terms of the interacting qubits, which is a scheme intrinsically fault-tolerant and therefore resilient to certain types of computational errors. Consequently, it has become a major challenge how to preserve entanglement of the quantum systems in the real situations [16][17][18][19][20][21].…”