Quantum Otto Heat Engine Research Based On Driven Dissipative Schrödinger Equation

Since Watt improved the steam engine at the end of the 17th century,it has greatly promoted the development of human industry and society,and even caused the industrial revolution in the 18th and 19th centuries.It has greatly changed the way of life of human society.But with the emergence of environment and energy efficiency problems,heat engines have required higher efficiency.The environmentally friendly internal combustion engine was born.In the 20th century,with the continuous development and improvement of quantum mechanics and the completeness of thermodynamic theory,the emergence of a new discipline—quantum thermodynamics has gradually brought more special quantum heat engines into people's field of vision and has become one of the hot topics in research.Since its emergence,people have been improving the performance of the quantum heat engine,which has made considerable progresses in many aspects,even breaking through the limit value under the classical model.Based on previous studies,we study the quantum Otto heat engine model using the dissipative Schrodinger equation,and conduct exploration and research in depth.We study the time evolution process of the heat engine's operating state.The influence of the different initial states including the coherent state is studied.In addition,we propose a new single-bath heat engine and study the engine performance affecting by some key parameters.Firstly,we probe the quantum Otto heat engine base on the excellent maneuverability of our method.We simulate the time evolution of the internal energy,power and heat conversion efficiency through numerical calculations.By adjusting the working time and making engine starts from different initial states,we can observe how the different initial states affect these thermodynamic quantities before the Otto cycle reaches stability.During the transition from the non-thermal equilibrium state to the thermal equilibrium state,we find that the efficiency and power may be higher or lower than the corresponding values in the stable operating state.It is worth noting that the efficiency can exceed the Otto limit or even the Carnot limit in this transient period.At the same time,the heat engine's power can be much higher than the rated power of the cyclostationary state.When the coherent state is introduced,we find that the performance of the heat engine in this situation is higher than the general situation(the ground state,the equal probability distribution on several lower energy levels),and further discuss the performance change in the case of high-fidelity coherent state.Secondly,we explore the thermodynamics by expanding the working time to ensure the machine reaching thermal equilibrium with the bath at last.Meanwhile,we show the time evolution process of internal energy and the time evolution of von Neumann entropy under decoherence conditions through numerical calculation.The validity of our model is further confirmed by comparing between the analytical solution and the numerical solution.In addition,we adjust the frequency ratio ?c/?h of the working medium of the heat engine,and find that the Carnot limit(1-Tc/Th)is the upper limit of the heat engine operating efficiency in the equilibrium state.Furthermore,we show that increasing the ambient temperature ratio under certain conditions is beneficial to enhance the thermal engine performance.In addition,based on the previous research,the energy stored in the heat engine can operate it at the initial moment.Therefore,we suggest that the periodically pumping can play a role similar to absorbing heat from a high-temperature heat source and can be manipulating flexibly.Furthermore,we propose a new type of quantum engine that operates stably in a single heat source environment,which can convert pump energy into mechanical work.This kind of manipulation engine can be applied to work in a microenvironment that does not have a large temperature difference,such as biological tissues in a living body.We respectively calculate time evolution starting from the first energy level excited state and the coherent state,and compare the differences between the two cases.,We find that this type of heat engine is more efficient in the coherent state,and its efficiency is close to the Otto limit.The optimum operating conditions are proposed.Finally,we introduce another work,comparative study of Peierls phase transition in quasi one-dimensional systems by X-ray diffraction and Raman spectra.By calculating and comparing the X-ray diffraction intensity of periodic lattice distortion and nonperiodic lattice distortion,we obtain that X-ray diffraction is difficult to distinguish extremely small distortions in single crystals.In addition,by analyzing the phonon dispersion relationship observed by Raman spectroscopy,we show that there is a large difference in phonon dispersion spectra in the above two cases,which clearly explains why Raman spectroscopy can better detect the tiny distortion in the crystal lattice.