We propose a nearly perfect optical scheme for the quantum teleportation of entangled coherent states using optical devices such as nonlinear Kerr media, beam splitters, phase shifters, and photon detectors. Different...We propose a nearly perfect optical scheme for the quantum teleportation of entangled coherent states using optical devices such as nonlinear Kerr media, beam splitters, phase shifters, and photon detectors. Different from those previous schemes, our scheme needs only ＂yes＂ or＂no＂ measurements of the photon number of the related modes, i.e. nonzero-and zero-photon measurements, while in previous schemes one has to exactly identify the even or odd parity character of the photon numbers detected by detectors.展开更多
In this paper, we study a quantum anti-Zeno effect (QAZE) purely induced by repetitive measurements foran artificial atom interacting with a structured bath.This bath can be artificially realized with coupled resonato...In this paper, we study a quantum anti-Zeno effect (QAZE) purely induced by repetitive measurements foran artificial atom interacting with a structured bath.This bath can be artificially realized with coupled resonators in onedimension and possesses photonic band structure like Bloch electron in a periodic potential.In the presence of repetitivemeasurements, the pure QAZE is discovered as the observable decay is not negligible even for the atomic energy levelspacing outside of the energy band of the artificial bath.If there were no measurements, the decay would not happenoutside of the band.In this sense, the enhanced decay is completely induced by measurements through the relaxationchannels provided by the bath.Besides, we also discuss the controversial golden rule decay rates originated from the vanHove's singularities and the effects of the counter-rotating terms.展开更多
We propose a scheme to enable a controllable cross-Kerr interaction between microwave photons in a circuit quantum electrodynamics （QED） system. In this scheme we use two transmission-line resonators （TLRs） and on...We propose a scheme to enable a controllable cross-Kerr interaction between microwave photons in a circuit quantum electrodynamics （QED） system. In this scheme we use two transmission-line resonators （TLRs） and one superconducting quantum interference device （SQUID） type charge qubit, which acts as an artificial atom. It is shown that in the dispersive regime of the eircuit-QED system, a controllable cross-Kerr interaction can be obtained by properly preparing the initial state of the qubit, and a large cross-phase shift between two microwave fields in the two TLRs can then be reached. Based on this cross-Kerr interaction, we show how to create a macroscopic entangled state between the two TLRs.展开更多
We study the quantum discord in a two-spin-1/2 XXZ model in thermal equilibrium at temperature T in the presence of an external magnetic field B. Special attention is paid to the dependence of quantum discord on the t...We study the quantum discord in a two-spin-1/2 XXZ model in thermal equilibrium at temperature T in the presence of an external magnetic field B. Special attention is paid to the dependence of quantum discord on the temperature T and magnetic field B. It is found that quantum thermal discord is more robust than concurrence against temperature, in the sense that quantum thermal discord does not vanish at finite temperatures, but concurrence vanishes completely at a critical temperature.展开更多
We study the spectrum of single-photon emission and scattering in a mixed optomechanical model which consists of both linear and quadratic optomechanical interactions.The spectra are calculated based on the exact long...We study the spectrum of single-photon emission and scattering in a mixed optomechanical model which consists of both linear and quadratic optomechanical interactions.The spectra are calculated based on the exact longtime solutions of the single-photon emission and scattering processes in this system.We find that there exist some phonon sideband peaks in the spectra and there are some sub peaks around the phonon sideband peaks under proper parameter conditions.The correspondence between the spectral features and the optomechanical interactions is confirmed, and the optomechanical coupling strengths can be inferred by analyzing the resonance peaks and dips in the spectra.展开更多
基金Project supported by the State Key Program of Basic Research of China （Grant No 2001CB309310）, the National Natural Science Foundation of China （Grant No 10325523）, and the Scientific Research Fund of Hunan Provincial Education Department, China （Grant No 04C385）.
文摘We propose a nearly perfect optical scheme for the quantum teleportation of entangled coherent states using optical devices such as nonlinear Kerr media, beam splitters, phase shifters, and photon detectors. Different from those previous schemes, our scheme needs only ＂yes＂ or＂no＂ measurements of the photon number of the related modes, i.e. nonzero-and zero-photon measurements, while in previous schemes one has to exactly identify the even or odd parity character of the photon numbers detected by detectors.
基金Supported by the National Natural Science Foundation of China under Grant Nos 10325523 and 10775048, the National Fundamental Research Program of China under Grant No 2007CB925204, and the Education Department of Hunan Province.
基金Supported by the Natural Science Foundation of China under Grant Nos.10974209 and 10935010 the National 973 Program under Grant No.2006CB921205China Postdoctoral Science Foundation under Grant No.20100470584
文摘In this paper, we study a quantum anti-Zeno effect (QAZE) purely induced by repetitive measurements foran artificial atom interacting with a structured bath.This bath can be artificially realized with coupled resonators in onedimension and possesses photonic band structure like Bloch electron in a periodic potential.In the presence of repetitivemeasurements, the pure QAZE is discovered as the observable decay is not negligible even for the atomic energy levelspacing outside of the energy band of the artificial bath.If there were no measurements, the decay would not happenoutside of the band.In this sense, the enhanced decay is completely induced by measurements through the relaxationchannels provided by the bath.Besides, we also discuss the controversial golden rule decay rates originated from the vanHove's singularities and the effects of the counter-rotating terms.
基金Supported by the National Fundamental Research Program Grant No 2007CB925204, the National Natural Science Foundation under Grant Nos 10325523, the Foundation of the Ministry of Education of China, and the Education Committee of Hunan Province.
基金supported by the National Natural Science Foundation of China (Grant Nos. 10775048 and 11075050)the National Basic Research Program of China (Grant No. 2007CB925204)the Education Department of Hunan Province,China (GrantNo. 08W012)
文摘We propose a scheme to enable a controllable cross-Kerr interaction between microwave photons in a circuit quantum electrodynamics （QED） system. In this scheme we use two transmission-line resonators （TLRs） and one superconducting quantum interference device （SQUID） type charge qubit, which acts as an artificial atom. It is shown that in the dispersive regime of the eircuit-QED system, a controllable cross-Kerr interaction can be obtained by properly preparing the initial state of the qubit, and a large cross-phase shift between two microwave fields in the two TLRs can then be reached. Based on this cross-Kerr interaction, we show how to create a macroscopic entangled state between the two TLRs.
基金Project supported by the National Fundamental Research Program of China (Grant No. 2007CB925204)the National Natural Science Foundation of China (Grant No. 10775048)+1 种基金the Key Project of the Chinese Ministry of Education (Grant No. 206103)the Construction Program of the National Key Discipline
文摘We study the quantum discord in a two-spin-1/2 XXZ model in thermal equilibrium at temperature T in the presence of an external magnetic field B. Special attention is paid to the dependence of quantum discord on the temperature T and magnetic field B. It is found that quantum thermal discord is more robust than concurrence against temperature, in the sense that quantum thermal discord does not vanish at finite temperatures, but concurrence vanishes completely at a critical temperature.
基金Supported by the National Natural Science Foundation of China under Grant Nos.11505055,11822501,11774087Natural Science Foundation of Hunan Province China under Grant No.2017JJ1021Scientific Research Fund of Hunan Provincial Education Department under Grant No.18A007
文摘We study the spectrum of single-photon emission and scattering in a mixed optomechanical model which consists of both linear and quadratic optomechanical interactions.The spectra are calculated based on the exact longtime solutions of the single-photon emission and scattering processes in this system.We find that there exist some phonon sideband peaks in the spectra and there are some sub peaks around the phonon sideband peaks under proper parameter conditions.The correspondence between the spectral features and the optomechanical interactions is confirmed, and the optomechanical coupling strengths can be inferred by analyzing the resonance peaks and dips in the spectra.
