The Optimal Maxwell's Demon In Quantum Szilard Engine

With the development of quantum mechanics,the understanding of physical phenomena has turned to the micro level.Many concepts of classical physics have been extended to the field of quantum physics,and many new disciplines have been formed,such as quantum informatics,quantum thermodynamics and so on.In recent years,the development of quantum theory and quantum information technology has promoted the development of quantum heat engines.Quantum heat engine is different from classical heat engine,because the working substance and principle of quantum heat engine are affected by quantum entanglement,quantum coherence,degeneracy and other quantum properties in quantum field.Quantum coherence and quantum entanglement are both useful physical resources.In the full quantum analysis of quantum Szilard heat engine,the coherence of Maxwell's demon quantum state is a useful resource of quantum Szilard heat engine,which has already been proved.This article mainly focuses on the measurement basis for Maxwell's demon,which has the corresponding influence on the quantum Szilard heat engine,and further learns the knowledge of quantum information and quantum thermodynamics through the above research.First,the relevant theoretical knowledge of thermodynamics and quantum mechanics is introduced.Then,quantum analysis of the working principle of the quantum Szilard heat engine and the specific processes of the quantum Szilard heat engine are carried out.Based on these,the quantum measurement process of the quantum Szilard heat engine is introduced,and it is pointed out that the efficiency of the quantum Szilard heat engine is related to the choice of the measure bases for the quantum Maxwell demo.The coherence of the quantum Maxwell demon depends on the choice of the reference base,so it is of great significance to choose the optimal reference base to obtain the maximum efficiency.Furthermore,we deduce the efficiency expression of the Maxwell demon-assisted quantum Szilard heat engine with quantum coherence.The efficiency of the quantum Szilard is related to the position of the board in the insertion process,which is reflected by the rotation angle of the reference baseand the probabilityof the particle on the right side after the board is inserted.We analyzed the heat engine efficiency when the two parameters took different values and calculated the optimal reference base and the corresponding quantum Szilard heat engine efficiency at this time.