Evolution processes of coupled thermal qubits

Yinghua Ji, Lin Xu

The evolution of entangled decoherence of coupling superconducting qubits in non-Markovian environment is investigated in detail using concurrence function.The results show that,for coupling superconducting qubit under different entangled initial states,because of the role of memory feedback due to environmental effect,the entanglement of coupling superconducting qubits under a thermal bath always tends to zero monotonically.Further results also showed that,the sudden death of entanglement will soon occur in non-Markovian process,stronger the dissipation,faster the death of entanglement.But in Markovian process,it tends to death of entanglement slowly.

G. L. Deçordi, A. Vidiella-Barranco

Mohammad Reza Eskandari, Ladan Rezaee

In this paper, we aim to provide a theoretical study of thermal entanglement of two qubits coupled to a spin chain with considering multiple-spin correlations which accompanies decay in multiple quantum nuclear magnetic resonance (MQ NMR) system. We show an explicit connection between the coherence factor and entanglement, and numerically and analytically study the dynamical process of entanglement in weak coupling cases for dipolar ordered initial states. We provide results that the entanglement evolution depends not only on the coupling constant between central two qubits and the system-environment couplings but also on temperature and the number of spins in chain.

R. Harris, A. J. Berkley, Mark W. Johnson +8 more

Leonid S Levitov, Terry P. Orlando, Johannes Majer +1 more

Jian-Song Zhang, Aixi Chen

We investigate the thermal influence of fibers on the dynamics of bipartite and multipartite correlations in fiber coupled cavity arrays where each cavity is resonantly coupled to a two-level atom. The atom-cavity systems connected by fibers can be considered as polaritonic qubits. We first derive a master equation to describe the evolution of the atom-cavity systems. The bipartite (multipartite) correlations are measured by concurrence and discord (spin squeezing). Then, we solve the master equation numerically and study the thermal effects on the concurrence, discord, and spin squeezing of the qubits. On the one hand, at zero temperature, there are steady state bipartite and multipartite correlations. On the other hand, the thermal fluctuations of a fiber may block the generation of entanglement of two qubits connected directly by the fiber, while the discord can be generated and stored for a long time. This thermal-induced blockade effects of bipartite correlations may be useful for quantum information processing. The bipartite correlations of a longer chain of qubits is more robust than a shorter one in the presence of thermal fluctuations.