Metastable decoherence-free subspaces and electromagnetically induced transparency in interacting many-body systems

We investigate the dynamics of a generic interacting many-body system under conditions of electromagnetically induced transparency (EIT). This problem is of current relevance due to its connection to non-linear optical media realized by Rydberg atoms. In an interacting system the structure of the dynamics and the approach to the stationary state becomes far more complex than in the case of conventional EIT. In particular, we discuss the emergence of a metastable decoherence free subspace, whose dimension for a single Rydberg excitation grows linearly in the number of atoms. On approach to stationarity this leads to a slow dynamics which renders the typical assumption of fast relaxation invalid. We derive analytically the effective non-equilibrium dynamics in the decoherence free subspace which features coherent and dissipative two-body interactions. We discuss the use of this scenario for the preparation of collective entangled dark states and the realization of general unitary dynamics within the spin-wave subspace.Comment: 13 pages, 3 figure

Quark condensate and magnetic moment in a strong magnetic field

This paper studies the quark condensate, magnetic moment, magnetic polarization, and magnetic susceptibility in a strong external magnetic field by employing the Dyson-Schwinger equations (DSE). The results show that these physical quantities as functions of the magnetic field. We note that the quark's spin polarizations are approximately proportional to the magnetic field magnitude. For comparison, we investigate the magnetic moments and susceptibility of the nucleon in the constituent quark model framework and demonstrate that both these quantities increase as the magnetic field rises.Comment: 10 pages, 5 figure

优质护理服务对骨科空巢患者心理障碍的应用效果

Objective: To investigate the effect of high quality nursing service in empty-nest patients of psychological barriers among orthopedic ward. Methods: 60 empty-nester patients were chosen from orthopedic ward, 30 patients treated with high quality care demonstration were the observation group and 30 patients treated with conventional care demonstration were the control group, 30 patients in control group were given the conventional nursing methods during hospitalization, observation group given the high quality nursing service, observe the nursing satisfaction in two groups. Results: Observation group nursing care and nurses job satisfaction are higher than the control group and the depression, psychological mood of anxiety in observation patients are lower than the control group，the difference was statistically significant (P<0.05). Conclusion: Using the high quality nursing service in empty-nest patients among orthopedic ward, could effectively relieve patients' anxiety and other negative emotions, improve patients care satisfaction experience of nursing care and nurses job satisfaction, help to promote the high quality nursing service demonstration project. 目的  探讨骨科空巢患者住院期间采取优质护理服务的应用效果。方法  选取60例骨科住院空巢患者，骨科优质护理示范病房收治的30例空巢患者为观察组，骨科非优质护理示范病房收治的30例空巢患者为对照组，对照组在住院期间给予常规护理方法，观察组在此基础上采用优质护理服务，观察两组护理满意度。结果  观察组的患者对护理工作满意度高于对照组，观察组空巢患者抑郁、焦虑的心理情绪低于对照组，观察组护士职业满意度高于对照组，差异有统计学意义（P<0.05）。结论  对骨科住院空巢焦虑患者采用优质护理服务，可有效减轻患者焦虑等负性情绪，