The loss of a quantum channel leads to an irretrievable particle loss as well as information. In this paper, the loss of quantum channel is analysed and a method is put forward to recover the particle and information ...The loss of a quantum channel leads to an irretrievable particle loss as well as information. In this paper, the loss of quantum channel is analysed and a method is put forward to recover the particle and information loss effectively using universal quantum error correction. Then a secure direct communication scheme is proposed, such that in a loss channel the information that an eavesdropper can obtain would be limited to arbitrarily small when the code is properly chosen and the correction operation is properly arranged.展开更多
We analyze entanglement properties of entangled coherent state （ECS）, ｜α,0） 1,2 ＋｜0,α） 1,2, with and without photon losses. By separating the coherent state into ]a） = co｜0） ＋ √-Co2｜α）, we derive exac...We analyze entanglement properties of entangled coherent state （ECS）, ｜α,0） 1,2 ＋｜0,α） 1,2, with and without photon losses. By separating the coherent state into ]a） = co｜0） ＋ √-Co2｜α）, we derive exact results of the logarithmic negativity EN, which quantifies the degree of entanglement between the two bosonic modes. Without particle losses, E~ = 1 for the NOON state; while for the ECS, E jr increases from 0 to 1 as ｜α｜-→∞. In the presence of photon losses, we find that the ECS with large enough photon number is more robust than that of the NOON state. An optimal ECS is obtained by maximizing E~ with respect to l a 12.展开更多
It is important to determine quantitatively the internal carrier loss arising from heating and barrier height variation in a vertical-cavity surface-emitting quantum well laser （VCSEL）. However, it is generally diff...It is important to determine quantitatively the internal carrier loss arising from heating and barrier height variation in a vertical-cavity surface-emitting quantum well laser （VCSEL）. However, it is generally difficult to realize this goal using purely theoretical formulas due to difficulty h, deriving the parameters relat^i~g to the quantum well structure. In this paper, we describe an efl：icient approach to characterizing and calculating the carrier loss due to the heating and the barrier height change in the VCSEL. In the method, the thermal carrier loss mechanism is combined with gain measurement and calculation. The carrier loss is re-characterized in a calculable form by constructing the threshold current and gain detuning-related loss current using the measured gain data and then substituting them for the quantum well-related parameters in the formula. The result can be expressed as a product of an exponential weight factor linked to the barrier height change and the difference between the threshold current and gain detuning-related loss current. The gain variation at cavity frequency due to thermal carrier loss and gain detuning processes is measured by using an AllnGaAs-AIGaAs VCSEL structure. This work provides a useful approach to analysing threshold and loss properties of the VCSEL, particularly, gain offset design for high temperature operation of VCSELs.展开更多
In this study the impact of quantum therapy on meat quality of slaughtered pigs was investigated.For this purpose the pigs were treated with different doses of magnet-infrared-laser(MIL) radiation.Animals were divided...In this study the impact of quantum therapy on meat quality of slaughtered pigs was investigated.For this purpose the pigs were treated with different doses of magnet-infrared-laser(MIL) radiation.Animals were divided into four groups according to radiation doses(4096,512,and 64 Hz,and control without application),which were applied in the lumbar area of musculus longissimus dorsi(loin) at various time intervals prior to the slaughter(14 d,24 h,and 1 h).Animals were slaughtered and the meat quality was evaluated by determining of pH value(1,3,and 24 h post slaughter),drip loss,colour,and lactic acid and phosphoric acid amounts.MIL therapy can be used in various fields of veterinary medicine as are surgery and orthopaedics,internal medicine,dentistry,pulmonology,gastroenterology,gynaecology,urology,nephrology,and dermatology.The results achieved showed that MIL radiation used in a short period before slaughter(1 h) can cause a change in the meat quality,as reflected by the non-standard development of pH values,increases in drip loss,and changes of meat colour.展开更多
基金Project supported by the National Natural Science Foundation of China （Grant No 10504042）.Acknowledgments We would like to thank Liu Wei-Tao, Wu Wei and Gao Ming for useful discussions.
文摘The loss of a quantum channel leads to an irretrievable particle loss as well as information. In this paper, the loss of quantum channel is analysed and a method is put forward to recover the particle and information loss effectively using universal quantum error correction. Then a secure direct communication scheme is proposed, such that in a loss channel the information that an eavesdropper can obtain would be limited to arbitrarily small when the code is properly chosen and the correction operation is properly arranged.
基金Project supported by the National Natural Science Foundation of China(Grant No.11174028)the Fundamental Research Funds for the Central Universities of China(Grant No.2011JBZ013)the Program for New Century Excellent Talents in University of China(Grant No.NCET-11-0564)
文摘We analyze entanglement properties of entangled coherent state （ECS）, ｜α,0） 1,2 ＋｜0,α） 1,2, with and without photon losses. By separating the coherent state into ]a） = co｜0） ＋ √-Co2｜α）, we derive exact results of the logarithmic negativity EN, which quantifies the degree of entanglement between the two bosonic modes. Without particle losses, E~ = 1 for the NOON state; while for the ECS, E jr increases from 0 to 1 as ｜α｜-→∞. In the presence of photon losses, we find that the ECS with large enough photon number is more robust than that of the NOON state. An optimal ECS is obtained by maximizing E~ with respect to l a 12.
文摘It is important to determine quantitatively the internal carrier loss arising from heating and barrier height variation in a vertical-cavity surface-emitting quantum well laser （VCSEL）. However, it is generally difficult to realize this goal using purely theoretical formulas due to difficulty h, deriving the parameters relat^i~g to the quantum well structure. In this paper, we describe an efl：icient approach to characterizing and calculating the carrier loss due to the heating and the barrier height change in the VCSEL. In the method, the thermal carrier loss mechanism is combined with gain measurement and calculation. The carrier loss is re-characterized in a calculable form by constructing the threshold current and gain detuning-related loss current using the measured gain data and then substituting them for the quantum well-related parameters in the formula. The result can be expressed as a product of an exponential weight factor linked to the barrier height change and the difference between the threshold current and gain detuning-related loss current. The gain variation at cavity frequency due to thermal carrier loss and gain detuning processes is measured by using an AllnGaAs-AIGaAs VCSEL structure. This work provides a useful approach to analysing threshold and loss properties of the VCSEL, particularly, gain offset design for high temperature operation of VCSELs.
文摘In this study the impact of quantum therapy on meat quality of slaughtered pigs was investigated.For this purpose the pigs were treated with different doses of magnet-infrared-laser(MIL) radiation.Animals were divided into four groups according to radiation doses(4096,512,and 64 Hz,and control without application),which were applied in the lumbar area of musculus longissimus dorsi(loin) at various time intervals prior to the slaughter(14 d,24 h,and 1 h).Animals were slaughtered and the meat quality was evaluated by determining of pH value(1,3,and 24 h post slaughter),drip loss,colour,and lactic acid and phosphoric acid amounts.MIL therapy can be used in various fields of veterinary medicine as are surgery and orthopaedics,internal medicine,dentistry,pulmonology,gastroenterology,gynaecology,urology,nephrology,and dermatology.The results achieved showed that MIL radiation used in a short period before slaughter(1 h) can cause a change in the meat quality,as reflected by the non-standard development of pH values,increases in drip loss,and changes of meat colour.
