We study the quantum discord dynamics of two noninteracting qubits that are, respectively, subject to classical noise. The results show that the dynamics of quantum discord are dependent on both the coupling between t...We study the quantum discord dynamics of two noninteracting qubits that are, respectively, subject to classical noise. The results show that the dynamics of quantum discord are dependent on both the coupling between the qubits and classical noise, and the average switching rate of the classical noise. In the weak-coupling Markovian region, quantum discord exhibits exponent decay without revival, and can be well protected by increasing the average classical noise switching rate. While in the strong-coupling non-Markovian region, quantum discord reveals slowly decayed oscillations with quick revival by decreasing the average switching rate of the classical noise. Thus, our results provide a new method of protecting quantum discord in a two-qubit system by controlling the coupling between the qubits and classical noise, and the average switching rate of the classical noise.展开更多
The influence of the extra classical noises in seed beams on the entanglement between the signal and the idler modes of the output fields generated by a non-degenerate optical parametric amplifier operating at deampli...The influence of the extra classical noises in seed beams on the entanglement between the signal and the idler modes of the output fields generated by a non-degenerate optical parametric amplifier operating at deamplification is investigated theoretically and experimentally. With the increase of the extra classical noises in the seed beams, the correlation degree of the output entangled optical fields, which is scaled by the quantum noise limit, decreases rapidly. The experimental results axe in good agreement with the theoretical calculations.展开更多
First we present a theoretical analysis of classical noise in ghost imaging system based on the coherent-mode representation theory. The classical noise depends crucially on the distribution of the eigenvalues of the ...First we present a theoretical analysis of classical noise in ghost imaging system based on the coherent-mode representation theory. The classical noise depends crucially on the distribution of the eigenvalues of the coherent-mode representation of the source and the decomposition coefficients of the object imaged. We show that both decreasing the distribution of the decomposition coefficients and increasing the distribution of the eigenvalues can lead to the decrease of classical noise.展开更多
We investigate the entanglement dynamics of a quantum system consisting of two two-level atoms in a cavity with classical driving fields in the presence of white noise. The cavity is initially prepared in the vacuum s...We investigate the entanglement dynamics of a quantum system consisting of two two-level atoms in a cavity with classical driving fields in the presence of white noise. The cavity is initially prepared in the vacuum state. Generally, the entanglement of two atoms decreases with the intensity of the thermal fields and the coupling strength of the two-level atoms to the thermal fields. However, we find that the entanglement of the quantum system can be enhanced by adjusting the frequency and the strength of the classical driving fields in the presence of white noise.展开更多
基金Projects supported by the National Natural Science Foundation of China(Grant No.11074072)
文摘We study the quantum discord dynamics of two noninteracting qubits that are, respectively, subject to classical noise. The results show that the dynamics of quantum discord are dependent on both the coupling between the qubits and classical noise, and the average switching rate of the classical noise. In the weak-coupling Markovian region, quantum discord exhibits exponent decay without revival, and can be well protected by increasing the average classical noise switching rate. While in the strong-coupling non-Markovian region, quantum discord reveals slowly decayed oscillations with quick revival by decreasing the average switching rate of the classical noise. Thus, our results provide a new method of protecting quantum discord in a two-qubit system by controlling the coupling between the qubits and classical noise, and the average switching rate of the classical noise.
基金supported by the National Natural Science Foundation of China (Grants Nos. 60736040 and 11074157)Project for Excellent Research Team of the National Natural Science Foundation of China (Grant No. 60821004)the National Basic Research Program of China (Grant No. 2010CB923103)
文摘The influence of the extra classical noises in seed beams on the entanglement between the signal and the idler modes of the output fields generated by a non-degenerate optical parametric amplifier operating at deamplification is investigated theoretically and experimentally. With the increase of the extra classical noises in the seed beams, the correlation degree of the output entangled optical fields, which is scaled by the quantum noise limit, decreases rapidly. The experimental results axe in good agreement with the theoretical calculations.
基金supported by the National Natural Science Foundation of China (Grant Nos. 10904015, 11074036, and 11004030)
文摘First we present a theoretical analysis of classical noise in ghost imaging system based on the coherent-mode representation theory. The classical noise depends crucially on the distribution of the eigenvalues of the coherent-mode representation of the source and the decomposition coefficients of the object imaged. We show that both decreasing the distribution of the decomposition coefficients and increasing the distribution of the eigenvalues can lead to the decrease of classical noise.
基金supported by the National Natural Science Foundation of China (Nos. 11065007 and 11047115)the Scientific Research Foundation of Jiangxi Provincial Department of Education (Nos. GJJ10135 and GJJ09504)the Foundation of Talent of Jinggang of Jiangxi Province (No. 2008DQ00400)
文摘We investigate the entanglement dynamics of a quantum system consisting of two two-level atoms in a cavity with classical driving fields in the presence of white noise. The cavity is initially prepared in the vacuum state. Generally, the entanglement of two atoms decreases with the intensity of the thermal fields and the coupling strength of the two-level atoms to the thermal fields. However, we find that the entanglement of the quantum system can be enhanced by adjusting the frequency and the strength of the classical driving fields in the presence of white noise.
