Quantum Thermodynamics In Trapped Ion System

Quantum thermodynamics studies the thermodynamic properties of quantum systems and explores the relationship between microscopic quantum properties and macroscopic thermodynamic laws.With the development of the theory and the manipulation technology of the quantum system,such as the systems of ultracold atoms,trapped ion and superconductor,more and more attention has been contributed to the theoretical and experimental research of quantum thermodynamics.Based on the trapped ion system,this paper discusses of the entropy exchange in the process of laser cooling and the physical realization quantum heat engine cycle.In the discussion of the entropy exchange during the laser cooling process of the single trapped ion,we firstly calculate the entropy increasement of a single photon in the spontaneous emission light field,and discuss the entropy exchange in the process of Doppler cooling.Then we construct a stimulated cooling cycle in the trapped ion system.Based on the definition of von Neumann entropy,the entropy exchange between atoms and environment in different forms of laser cooling is calculated.We find that the spontaneous emission is not the only way to transfor the entropy between the atomic system and the environment.The entropy capacity of the laser field is big enough to undertake the entropy reduction of the atomic system,and the second and third laws of thermodynamics are still valid in the laser cooling atoms process.On the research of quantum heat engine,we introduce the processes of quantum heat engine cycle in the trapped ion system,and calculate the efficiency and power of the heat engine under different conditions.On this basis,we introduce the influence of the introduction of quantum properties of the thermal reservoir on the performance of the heat engine,and take the nonclassical squeezed thermal reservoir as the example.We find that the introduction of quantum properties will greatly affect the performance of the heat engine,and different ways of introducing the same quantum properties may bring different effects.Furthermore,we propose an experimental scheme to construct an ultralow temperature quantum heat engine cycle in the parallel shaped trapped ion system.