Considering a grand canonical ensemble,we study the phase structures and transitions of RN black holes surrounded by quintessence dark energy on two different boundary conditions,namely AdS space and a Dirichlet wall....Considering a grand canonical ensemble,we study the phase structures and transitions of RN black holes surrounded by quintessence dark energy on two different boundary conditions,namely AdS space and a Dirichlet wall.For AdS space,under the condition of fixed temperature and potential,as the temperature increases for lower potential,the black hole undergoes a first-order phase transition,while for higher potential,no phase transition occurs.There are two different regions in the parameter space.For the Dirichlet wall,on which the temperature and potential are fixed,the state parameter of quintessenceω=-2/3 is analyzed in detail.Then,three different physically allowed regions in the parameter space of the black hole are well studied.As the temperature rises,first-order and second-order phase transitions may occur.In this case,there are nine regions in the parameter space,which is evidently distinct from the case of AdS space.展开更多
The thermal decoherence of harmonic oscillators is investigated here.The quantum system presented here is a one-dimensional oscillator with angular frequency,which is surrounded by a thermal bath of environmental osci...The thermal decoherence of harmonic oscillators is investigated here.The quantum system presented here is a one-dimensional oscillator with angular frequency,which is surrounded by a thermal bath of environmental oscillators.There are various environmental oscillators with different angular frequency(below an ultraviolet cutoff).At the beginning,the quantum system is a pure state and the environmental oscillators are in thermodynamic equilibrium with temperature.After a period,the system-environment interactions inspire significant decoherence of the quantum state.Such decoherence is displayed by explicit calculations of the purity and von Neumann entropy of the quantum system.It is worth noting that the decoherence could be significant even in the weak coupling and low temperature case due to the large amount of environmental degrees of freedom.Since the decoherence process is inspired between the quantum system and an ordinary thermal environment here,the thermal decoherence result is quite general.展开更多
基金Supported by National Natural Science Foundation of China (NSFC) (11947408)。
文摘Considering a grand canonical ensemble,we study the phase structures and transitions of RN black holes surrounded by quintessence dark energy on two different boundary conditions,namely AdS space and a Dirichlet wall.For AdS space,under the condition of fixed temperature and potential,as the temperature increases for lower potential,the black hole undergoes a first-order phase transition,while for higher potential,no phase transition occurs.There are two different regions in the parameter space.For the Dirichlet wall,on which the temperature and potential are fixed,the state parameter of quintessenceω=-2/3 is analyzed in detail.Then,three different physically allowed regions in the parameter space of the black hole are well studied.As the temperature rises,first-order and second-order phase transitions may occur.In this case,there are nine regions in the parameter space,which is evidently distinct from the case of AdS space.
文摘The thermal decoherence of harmonic oscillators is investigated here.The quantum system presented here is a one-dimensional oscillator with angular frequency,which is surrounded by a thermal bath of environmental oscillators.There are various environmental oscillators with different angular frequency(below an ultraviolet cutoff).At the beginning,the quantum system is a pure state and the environmental oscillators are in thermodynamic equilibrium with temperature.After a period,the system-environment interactions inspire significant decoherence of the quantum state.Such decoherence is displayed by explicit calculations of the purity and von Neumann entropy of the quantum system.It is worth noting that the decoherence could be significant even in the weak coupling and low temperature case due to the large amount of environmental degrees of freedom.Since the decoherence process is inspired between the quantum system and an ordinary thermal environment here,the thermal decoherence result is quite general.
