Quantum Battery with Ultracold Atoms: Bosons vs. Fermions

Abstract

We design a quantum battery made up of bosons or fermions in an ultracold atom setup, described by Fermi-Hubbard (FH) and Bose-Hubbard (BH) models respectively. We compare the performance of bosons as well as fermions and check which can act more efficiently as a quantum battery for a given on-site interaction and temperature of the initial state. The performance of a quantum battery is quantified by the maximum power generated over the time evolution under an on-site charging Hamiltonian. We report that when the initial battery state is in the ground state, fermions outperform bosons in a certain configuration over a large range of on-site interactions which are shown analytically for a smaller number of lattice sites and numerically for a considerable number of sites. Bosons take the lead when the temperature is comparatively high in the initial state for a longer range of on-site interaction. We perform the study of a number of up and down fermions as well as the number of bosons per site to find the optimal filling factor for maximizing the power of the battery. We also introduce disorder in both on-site and hopping parameters and demonstrate that the maximum power is robust against impurities. Moreover, we identify a range of tuning parameters in the fermionic as well as bosonic systems where the disorder-enhanced power is observed.