Charging Performance Of Quantum Battery Based On Ultracold Atomic Systems

As a type of energy storage device,batteries have been widely used in various fields such as electronics,medical science,and computers.With the advancement of technology,various devices are rapidly developing towards miniaturization and gradually reaching the molecular or even atomic scale,where the influence of quantum effects must be considered.Against this background,exploring a type of quantum system that can effectively store and extract energy,namely quantum batteries,has become an important research topic in the field of quantum technology.In recent years,many research has been devoted to optimising the charge and discharge performance of quantum batteries and exploring possible solutions for their implementation schemes.Ultracold atomic systems,with their advantages of cleanliness and ease of manipulation,have become one of the ideal simulation platforms for realizing quantum batteries,with broad application prospects.However,currently proposed ultracold atomic quantum batteries have low charging efficiency.Therefore,it is of great significance to explore ultracold atomic quantum batteries with higher charging efficiency.In this thesis,we investigate two different types of ultracold atomic quantum batteries,analytically solvable Rosen-Zener quantum battery and efficient Hubbard quantum battery,using gauge transformation and variational super-adiabatic techniques.Firstly,we investigate the Rosen-Zener quantum battery with particle-particle interactions under external driving via gauge transformation method,which achieves efficient and stable charging process.The analytical solution of the quantum battery was obtained,and the charging performance was analyzed.We also find the mechanism of the external driving field intensity,scanning period,and atomic interactions in the charging process of the quantum battery.We find that the analytical and numerical solutions are in good agreement when the atomic interaction and the scanning period are small,and full charging can be achieved when the external driving field parameters satisfy a quantitative relationship.At the end of the charging process,the stored energy is negatively correlated with energy fluctuations and entanglement,and the energy fluctuations behave consistently with entanglement.Furthermore,the maximum stored energy reaches its maximum value at the quantum phase transition point.These results provide theoretical support for the realization of efficient Rosen-Zener quantum battery.Secondly,we investigate the Hubbard quantum battery with particle-particle interactions by using the variational superadiabatic technique to achieve efficient charging process.The additional Hamiltonian required for superadiabatic was obtained,and the mechanism of particle-particle interactions,entanglement between the battery and charger in the charging process was revealed.We also analyze the energy cost required for the application of the adiabatic charging technique.We find that the variational adiabatic technique could optimise the charging performance of the Hubbard quantum battery by increasing the stored energy and improving the charging efficiency.Compared to Bosons quantum battery,Fermions quantum battery have higher charging power but consumed more energy cost.In addition,the stored energy of the Hubbard quantum battery is negatively correlated with the energy uncertainty and entanglement,i.e.,the maximum value of stored energy corresponds to the minimum value of energy quantum fluctuation and von Neumann entropy.This research provides a theoretical basis for the realisation of highly efficient Hubbard quantum battery.