The performance of a two-state quantum engine under different conditions is analyzed.It is shown that the efficiency of the quantum engine can be enhanced by superposing the eigenstates at the beginning of the cycle.B...The performance of a two-state quantum engine under different conditions is analyzed.It is shown that the efficiency of the quantum engine can be enhanced by superposing the eigenstates at the beginning of the cycle.By employing the finite-time movement of the potential wall,the power output of the quantum engine as well as the efficiency at the maximum power output(EMP) can be obtained.A generalized potential is adopted to describe a class of two-level quantum engines in a unified way.The results obtained show clearly that the performances of these engines depend on the external potential,the geometric configuration of the quantum engines,and the superposition effect.Moreover,it is found that the superposition effect will enlarge the optimally operating region of quantum engines.展开更多
Based on the thermodynamic properties of isoenergetic,adiabatic and isothermal quantum processes,it is shown that it is possible to combine the three processes into a quantum engine cycle.The efficiency of the three-p...Based on the thermodynamic properties of isoenergetic,adiabatic and isothermal quantum processes,it is shown that it is possible to combine the three processes into a quantum engine cycle.The efficiency of the three-process cycle can be derived and is dependent on the highest and lowest temperatures.The efficiency in some operation regions does not demonstrate a monotonically increasing function of the temperature difference.When the highest temperature of the cycle is larger than the critical temperature,which can be determined by the characteristics of the three-process cycle,a unique region where the efficiency decreased with the increase of the temperature difference exists.展开更多
Tsallis entropy and incomplete entropy are proven to have equivalent mathematical structure except for one nonextensive factor q through variable replacements on the basis of their forms. However, employing the Lagran...Tsallis entropy and incomplete entropy are proven to have equivalent mathematical structure except for one nonextensive factor q through variable replacements on the basis of their forms. However, employing the Lagrange multiplier method, it is judged that neither yields the q-exponential distributions that have been observed for many physical systems. Consequently, two generalized entropies under complete and incomplete probability normalization conditions are proposed to meet the experimental observations. These two entropic forms are Lesche stable, which means that both vary continuously with probability distribution functions and are thus physically meaningful.展开更多
Based on the q-exponential distribution which has been observed in more and more physical systems, the uncertainty measure of such an abnormal distribution can be derived by employing a variational relationship which ...Based on the q-exponential distribution which has been observed in more and more physical systems, the uncertainty measure of such an abnormal distribution can be derived by employing a variational relationship which can be traced from the first and second thermodynamic laws. The uncertainty measure obtained here can be considered as the entropic form for the abnormal physical systems having observable q-exponential distribution. This entropy will tend to the Boltzmann-Gibbs entropy when the nonextensive parameter tends to unity. It is very important to find that this entropic form is always concave and the systemic entropy is maximizable.展开更多
This work reports on numerical simulations of Brownian motion in the non-dissipative limit. The objective was to prove the existence of path probability and to compute probability values for some sample paths. By simu...This work reports on numerical simulations of Brownian motion in the non-dissipative limit. The objective was to prove the existence of path probability and to compute probability values for some sample paths. By simulating a large number of particles moving from point to point under Gaussian noise and conservative forces, we numerically determine that the path probability decreases exponentially with increasing Lagrangian action of the paths.展开更多
基金supported by the National Natural Science Foundation of China(Grant No.11005041)the Program for Prominent Young Talents in Fujian Province University(Grant No.JA12001)+2 种基金the Natural Science Foundation of Fujian Province(Grant Nos.2010J05007 and 2011J01012)the Fundamental Research Funds for the Central Universities(Grant No.JB-SJ1005)the Science Research Fund of Huaqiao University(Grant No.09BS510)
文摘The performance of a two-state quantum engine under different conditions is analyzed.It is shown that the efficiency of the quantum engine can be enhanced by superposing the eigenstates at the beginning of the cycle.By employing the finite-time movement of the potential wall,the power output of the quantum engine as well as the efficiency at the maximum power output(EMP) can be obtained.A generalized potential is adopted to describe a class of two-level quantum engines in a unified way.The results obtained show clearly that the performances of these engines depend on the external potential,the geometric configuration of the quantum engines,and the superposition effect.Moreover,it is found that the superposition effect will enlarge the optimally operating region of quantum engines.
基金supported by the National Natural Science Foundation of China(Grant Nos.11005041 and 11247265)the Program for Prominent Young Talents in Fujian Province University(Grant No.JA12001)+1 种基金the Scientific Research Foundation for the Returned Overseas Chinese Schol-ars(Grant No.2010-1561)the Promotion Program for Young and Middle-aged Teacher in Science and Technology Research of Huaqiao University(Grant No.ZQN-PY114)
文摘Based on the thermodynamic properties of isoenergetic,adiabatic and isothermal quantum processes,it is shown that it is possible to combine the three processes into a quantum engine cycle.The efficiency of the three-process cycle can be derived and is dependent on the highest and lowest temperatures.The efficiency in some operation regions does not demonstrate a monotonically increasing function of the temperature difference.When the highest temperature of the cycle is larger than the critical temperature,which can be determined by the characteristics of the three-process cycle,a unique region where the efficiency decreased with the increase of the temperature difference exists.
基金supported by the National Natural Science Foundation of China (11005041)Natural Science Foundation of Fujian Province (2010J05007)Scientific Research Foundation for the Returned Overseas Chinese Scholars and Basic Science Research Foundation of Huaqiao University (JB-SJ1005)
文摘Tsallis entropy and incomplete entropy are proven to have equivalent mathematical structure except for one nonextensive factor q through variable replacements on the basis of their forms. However, employing the Lagrange multiplier method, it is judged that neither yields the q-exponential distributions that have been observed for many physical systems. Consequently, two generalized entropies under complete and incomplete probability normalization conditions are proposed to meet the experimental observations. These two entropic forms are Lesche stable, which means that both vary continuously with probability distribution functions and are thus physically meaningful.
基金supported by the National Natural Science Foundation of China (11005041)Natural Science Foundation of Fujian Province(2010J05007)+2 种基金Scientific Research Foundation for the Returned Overseas Chinese ScholarsFundamental Research Funds for the Central Universities (JB-SJ1005)Programme of Introducing Talents of Discipline to Universities (B08033)
文摘Based on the q-exponential distribution which has been observed in more and more physical systems, the uncertainty measure of such an abnormal distribution can be derived by employing a variational relationship which can be traced from the first and second thermodynamic laws. The uncertainty measure obtained here can be considered as the entropic form for the abnormal physical systems having observable q-exponential distribution. This entropy will tend to the Boltzmann-Gibbs entropy when the nonextensive parameter tends to unity. It is very important to find that this entropic form is always concave and the systemic entropy is maximizable.
基金supported by the Region des Pays de la Loire in France(2007-6088 and 2009-09333)
文摘This work reports on numerical simulations of Brownian motion in the non-dissipative limit. The objective was to prove the existence of path probability and to compute probability values for some sample paths. By simulating a large number of particles moving from point to point under Gaussian noise and conservative forces, we numerically determine that the path probability decreases exponentially with increasing Lagrangian action of the paths.