Towards Optimal Charging of a Many-Body Quantum Battery*

Understanding the charging of experimentally relevant quantum battery models has been of great recent interest in the field of quantum thermodynamics. We study the problem of optimally charging a battery consisting of an interacting many-body quantum system using non-gradient based numerical techniques. Starting from the ground state of the 1D transverse ising model (1D-TIM), we obtain optimal control fields for maximizing the ergotropy of the system, thereby giving rise to a charged quantum battery.

We report on the role played by anisotropy in the exchange interactions of the 1D-TIM and contrast the importance of defect density from the theory of quantum phase transitions with ergotropy for the optimal charging protocol. Using this setup on the 1D-TIM with additional longitudinal fields enables us to investigate the effect of the presence of phase transitions in the system on the charging protocols and performance. Furthermore, we explore the importance of integrability for our charging protocols and the independence of the optimised charging advantage with system size.