The decoherence of two initially entangled qubits coupled with a squeezed vacuum cavity separately is investigated exactly. The results show that, first, in principle, the disentanglement time decreases with the incre...The decoherence of two initially entangled qubits coupled with a squeezed vacuum cavity separately is investigated exactly. The results show that, first, in principle, the disentanglement time decreases with the increase of squeeze parameter r, due to the augmenting of average photon number of every mode in the squeezed vacuum cavity. Second, there appear entanglement revivals after the complete disentanglement for the ease of even parity initial Bell state, while there occur the entanglement decrease and the entanglement revival before the complete disentanglement for the case of odd parity initial Bell state. The results are quite different from those for the case of qubits in a vacuum cavity.展开更多
The quantum speed limit time for quantum system under squeezed environment is studied.We consider two typical models,the damped Jaynes-Cummings model and the dephasing model.For the damped Jaynes-Cummings model under ...The quantum speed limit time for quantum system under squeezed environment is studied.We consider two typical models,the damped Jaynes-Cummings model and the dephasing model.For the damped Jaynes-Cummings model under squeezed environment,we find that the quantum speed limit time becomes larger with the squeezed parameter r increasing and indicates symmetry about the phase parameter valueθ=π.Meanwhile,the quantum speed limit time can also be influenced by the coupling strength between the system and environment.However,the quantum speed limit time for the dephasing model is determined by the dephasing rate and the boundary of acceleration region that interacting with vacuum reservoir can be broken when the squeezed environment parameters are appropriately chosen.展开更多
基金supported by the National Natural Science Foundation of China (Grant No 60578055)the State Key Program for Basic Research of China (Grant Nos 2007CB925204 and 2007CB307001)
文摘The decoherence of two initially entangled qubits coupled with a squeezed vacuum cavity separately is investigated exactly. The results show that, first, in principle, the disentanglement time decreases with the increase of squeeze parameter r, due to the augmenting of average photon number of every mode in the squeezed vacuum cavity. Second, there appear entanglement revivals after the complete disentanglement for the ease of even parity initial Bell state, while there occur the entanglement decrease and the entanglement revival before the complete disentanglement for the case of odd parity initial Bell state. The results are quite different from those for the case of qubits in a vacuum cavity.
基金Project supported by the National Natural Science Foundation of China(Grant No.11775040)the Scientific and Technological Innovation Program of the Higher Education Institutions of Shanxi Province,China(Grant No.2019L0527).
文摘The quantum speed limit time for quantum system under squeezed environment is studied.We consider two typical models,the damped Jaynes-Cummings model and the dephasing model.For the damped Jaynes-Cummings model under squeezed environment,we find that the quantum speed limit time becomes larger with the squeezed parameter r increasing and indicates symmetry about the phase parameter valueθ=π.Meanwhile,the quantum speed limit time can also be influenced by the coupling strength between the system and environment.However,the quantum speed limit time for the dephasing model is determined by the dephasing rate and the boundary of acceleration region that interacting with vacuum reservoir can be broken when the squeezed environment parameters are appropriately chosen.
