In an electromagnetically induced transparency system,the atoms have long-lived coherence compared to the cavity lifetime and interact nonadiabatically with the laser fields.We show that the high frequency fluctuation...In an electromagnetically induced transparency system,the atoms have long-lived coherence compared to the cavity lifetime and interact nonadiabatically with the laser fields.We show that the high frequency fluctuations of both the intensities and the intensity difference can be squeezed below the shot noise limit due to the nonadiabatic effects.This noise squeezing can be used to enhance the precision in the short time measurements based on the intensities or the intensity difference.展开更多
Effects of detunings on dynamically induced irreversibility is studied for coherently driven V systems in which there is no conventional source of irreversible population pumping.For atomic barium(γ1/γ2=400>>1...Effects of detunings on dynamically induced irreversibility is studied for coherently driven V systems in which there is no conventional source of irreversible population pumping.For atomic barium(γ1/γ2=400>>1,whereγ1 andγ2 are the rates of the spontaneous decay from the excited states 6s6p^(1)P_(1)and 6s6p^(3)P_(1)to the ground state 6s^(2)^(1)S_(0),respectively),the strong irreversibility is found to lead to a maximum inversion of 0.77[only 0.1 in Phys.Rev.Lett.71(1993)4311].The maximum population inversion requires relatively strong Gelds coupled respectively to two transitions,a disparity in two atomic decay rates,and the atom-field detunings of opposite signs.However,it is also shown that even in the cases where two detunings have the same sign,or where two decay rates are equal,population inversion takes place.展开更多
A quantum-beat laser without inversion is proposed for producing two-mode suqeezing.Using the dressed-atom-dressed-mode approach,the master equation is derived and the variances in the sum mode intensity and in the re...A quantum-beat laser without inversion is proposed for producing two-mode suqeezing.Using the dressed-atom-dressed-mode approach,the master equation is derived and the variances in the sum mode intensity and in the relative amplitude and phase are calculated.When the laser is operated well above threshold,the intensity fluctuations in the sum mode are reduced below the shot noise limit with an optimum Mandel parameter of-0.5.At the same time,the fluctuations in the relative amplitude and phase are retained at their vaccum noise levels.展开更多
The effects of the pump phase fluctuation on aΛ-laser with and without inversion are investigated.It is shown that the pump phase fluctuation can reduce the linewidth of the laser without inversion.It is also shown t...The effects of the pump phase fluctuation on aΛ-laser with and without inversion are investigated.It is shown that the pump phase fluctuation can reduce the linewidth of the laser without inversion.It is also shown that,when the system exhibits a transition from lasing without inversion to lasing with inversion,the laser linewidth can still be reduced.展开更多
Noise squeezing of intensity difference between the pair of sum modes may be generated in a cascade laser of A and U quantum-beats.The best achievable squeezing is up to 50%below the shot noise limit.This new kind of ...Noise squeezing of intensity difference between the pair of sum modes may be generated in a cascade laser of A and U quantum-beats.The best achievable squeezing is up to 50%below the shot noise limit.This new kind of squeezed lasers has potential for quantum communications and precision measurements.展开更多
Background Sleep disorders have been found in patients with infective endocarditis(IE)and are reported to have a strong correlation with inflammation. In this study,we measured the serum levels of inflammatory factors...Background Sleep disorders have been found in patients with infective endocarditis(IE)and are reported to have a strong correlation with inflammation. In this study,we measured the serum levels of inflammatory factors and evaluated the correlations of postoperative sleep efficiency with C-reactive protein and interleukin-6(IL-6)in IE patients. Methods A total of 117 post-operative patients with IE were enrolled in the study. All patients were tested using a wearable actigraphy device for their sleep efficiency. All patients were examined for C-reactive protein,and 72 patients were tested for IL-6. Results A correlation analysis was performed between C-reactive protein and IL-6. The average sleep efficiency of most of the IE patients was 80.81±8.52%,and the average result of the C-reactive protein test was 29.98±26.3 mg/L. The correlation coefficient between sleep efficiency and C-reactive protein was-0.3011. The average result of the IL-6 test was 24.52±23.85 pg/mL,and the correlation coefficient between sleep efficiency and IL-6 was-0.3543. Conclusions Postoperative sleep efficiency is negatively correlated with serum levels of C-reactiveprotein and IL-6 in patients with IE.[S Chin J Cardiol2019;20(2):103-107]展开更多
基金by the National Natural Science Foundation of China under Grant No 11074086.
文摘In an electromagnetically induced transparency system,the atoms have long-lived coherence compared to the cavity lifetime and interact nonadiabatically with the laser fields.We show that the high frequency fluctuations of both the intensities and the intensity difference can be squeezed below the shot noise limit due to the nonadiabatic effects.This noise squeezing can be used to enhance the precision in the short time measurements based on the intensities or the intensity difference.
基金Supported by the National Natural Science Foundation of China under Grant No.69708001the Natural Science Foundation of Hubei Province under Grant No.97J013.
文摘Effects of detunings on dynamically induced irreversibility is studied for coherently driven V systems in which there is no conventional source of irreversible population pumping.For atomic barium(γ1/γ2=400>>1,whereγ1 andγ2 are the rates of the spontaneous decay from the excited states 6s6p^(1)P_(1)and 6s6p^(3)P_(1)to the ground state 6s^(2)^(1)S_(0),respectively),the strong irreversibility is found to lead to a maximum inversion of 0.77[only 0.1 in Phys.Rev.Lett.71(1993)4311].The maximum population inversion requires relatively strong Gelds coupled respectively to two transitions,a disparity in two atomic decay rates,and the atom-field detunings of opposite signs.However,it is also shown that even in the cases where two detunings have the same sign,or where two decay rates are equal,population inversion takes place.
基金Supported by the National Natural Science Foundation of China under Grant No.69708001the Natural Science Foundation of Hubei Province under Grant No.97J013.
文摘A quantum-beat laser without inversion is proposed for producing two-mode suqeezing.Using the dressed-atom-dressed-mode approach,the master equation is derived and the variances in the sum mode intensity and in the relative amplitude and phase are calculated.When the laser is operated well above threshold,the intensity fluctuations in the sum mode are reduced below the shot noise limit with an optimum Mandel parameter of-0.5.At the same time,the fluctuations in the relative amplitude and phase are retained at their vaccum noise levels.
基金Supported by the National Natural Science Foundation of China under Grant No.69708001the National Natural Science Foundation of Hubei Province under Grant No.97J013。
文摘The effects of the pump phase fluctuation on aΛ-laser with and without inversion are investigated.It is shown that the pump phase fluctuation can reduce the linewidth of the laser without inversion.It is also shown that,when the system exhibits a transition from lasing without inversion to lasing with inversion,the laser linewidth can still be reduced.
基金the National Natural Science Foundation of China under Grant No.69708001the Natural Science Foundation of Hubei Province under Grant No.97J013.
文摘Noise squeezing of intensity difference between the pair of sum modes may be generated in a cascade laser of A and U quantum-beats.The best achievable squeezing is up to 50%below the shot noise limit.This new kind of squeezed lasers has potential for quantum communications and precision measurements.
基金supported by Science and Technology Planning Project of Guangdong Province(No.A2016057/B2015093)
文摘Background Sleep disorders have been found in patients with infective endocarditis(IE)and are reported to have a strong correlation with inflammation. In this study,we measured the serum levels of inflammatory factors and evaluated the correlations of postoperative sleep efficiency with C-reactive protein and interleukin-6(IL-6)in IE patients. Methods A total of 117 post-operative patients with IE were enrolled in the study. All patients were tested using a wearable actigraphy device for their sleep efficiency. All patients were examined for C-reactive protein,and 72 patients were tested for IL-6. Results A correlation analysis was performed between C-reactive protein and IL-6. The average sleep efficiency of most of the IE patients was 80.81±8.52%,and the average result of the C-reactive protein test was 29.98±26.3 mg/L. The correlation coefficient between sleep efficiency and C-reactive protein was-0.3011. The average result of the IL-6 test was 24.52±23.85 pg/mL,and the correlation coefficient between sleep efficiency and IL-6 was-0.3543. Conclusions Postoperative sleep efficiency is negatively correlated with serum levels of C-reactiveprotein and IL-6 in patients with IE.[S Chin J Cardiol2019;20(2):103-107]
