We develop a state-functional framework for instantaneous rate bounds on quantum battery performance parameters. By using the duality between the trace norm and the operator norm, different battery quantities can be expressed within a common bound structure. Energetic, extractable work, and information-theoretic quantities are treated as functionals of the reduced battery state. For each functional, a sensitivity operator separates the bound into a universal trace-norm speed and a parameter-dependent spectral sensitivity factor, and also determines the equality condition. We apply the framework to the charging power, the ergotropy rate, and the change rate of purity in Jaynes-Cummings, anisotropic Rabi, central-spin, and $\mathit{XY}$ spin-chain batteries. The results show that these rates share the same state space speed, while their approach to equality depends on the corresponding sensitivity operator and on the reduced-state dynamics. Counter-rotating wave terms and many-body couplings do not invalidate the bounds, but modify their saturation behavior. Overall, the framework is model independent and provides general limits for battery performance parameters.

Close

PrevNext

View figure in article

• Quantum correlations, foundations & formalism
• Quantum information processing
• Quantum information theory