We propose and investigate the performance of a hybrid quantum battery, the
so-called Kerr quantum battery, which consists of two interacting quantum
oscillators, i.e., the charger is a harmonic oscillator and the battery is an
anharmonic oscillator involving the Kerr nonlinearity. Such a setup creates
nonuniform spacing between energy levels of the quantum oscillator that
increases with the energy level. We find that the Kerr quantum battery can
store more energy than the qubit battery and reaches maximum stored energy
faster than the harmonic oscillator battery. In particular, the average
charging power of the Kerr quantum battery is larger than the qubit battery.
Furthermore, most of the stored energy in the Kerr quantum battery can be
extracted for work. All of the properties of the Kerr quantum battery are
controlled by the strength of nonlinearity, in which the enhancement of the
nonlinearity transforms the battery from a harmonic oscillator to a qubit.Comment: 5 pages, 5 figures, submitted to Appl. Phys. Let