Effect of feedback control on the entanglement evolution

Qing Yang, Hui Liu, Xiu-Lan Zhen +2 more

The entanglement dynamics of two identical atoms coupled to a single-mode cavity is considered. Based on the reduced non-perturbative quantum master equation method, the entanglement evolution of the two atoms with spontaneous emission under the quantum-jump-based feedback control is investigated beyond the conventional rotating-wave approximation (RWA). The research of entanglement evolution beyond RWA is a significant problem because of its importance to the field of strong coupling. The result of numerical simulations shows that an appropriate feedback control can prolong the entanglement time and increase the entanglement amplitude. The effect of synchronous control on two atoms is superior to that of one control.

S. Mancini, J. Wang

Mohamed Amazioug, Jia‐Xin Peng, Denys Dutykh +1 more

Jin Wang, Thomas Sutter, Magnolia Landman +1 more

This paper studies the ability of feedback control to reduce the effect of decoherence and enhance entanglement in an interacting spin-1/2 XY dimer model in the presence of a transverse magnetic field. The system reaches an improved steady state entanglement when feedback is present. The influence of the strength of the external B field is found for optimized steady state entanglement. The time-dependent entanglement evolution of the system is also studied. One potential application of this scheme is to raise the maximum operating temperature of spin entangled systems.

Xin Liu, Guangyu Fang, Qinghong Liao +1 more

Abolghasem Daeichian, Mehdi Mirzaee

Abstract Expanding utilization of entangled states in quantum technologies, such as quantum information, is a motivating force of developing new methods for enhancement and stabilization of quantum entanglement. This study focuses on using asymmetric lawsto control the entangled states of a quantum systemconsistingof two atoms, each confined in a cavity.The effect of asymmetry laws has been explored in three different scenarios. First, the effect of an asymmetric drive Hamiltonian on a closed quantum system, in which neither the cavity nor the atoms exhibit losses, is studied. Here, the eigenvalues and eigenstates of the total system Hamiltonian have been obtained and the time evolution of the system state has been derived. Also, the fidelity of the system in terms of the asymmetric drive Hamiltonian has been derived analytically. In the second scenario, the stationary solution of an open quantum system, which includes losses in a master equation approach, is derived and the concurrence is studied in terms of the asymmetric drive Hamiltonian and coupling constant. The last scenario is devoted to applying feedback rulesto an open quantum system where some heuristic feedback control laws have been proposed. The simulation results show the concurrence boosting in a larger range of driving field and feedback strength when applying the introduced feedback rules.