Description
Quantum batteries offer the prospect of achieving charging advantages beyond those attainable in classical or independently charged systems by exploiting quantum resources for energy storage. In particular, collective charging can enhance the charging power relative to the parallel charging of individual cells, with quantitative bounds and scaling laws established in many-body battery models. However, current implementations of quantum batteries are constrained by the limited energy density and short retention times associated with optical or molecular excitations.
We propose a nuclear quantum battery based on collective excitation of $^{57}$Fe nuclei of density $n$ embedded in a planar hard x-ray waveguide. Using a Green's-function waveguide-QED description, we study charging beyond linear response, where saturation and drive back-action reshape the incident pulse. We introduce a self-consistent waveform-engineering protocol that suppresses local radiative leakage in the waveguide, thereby promoting absorption into high-lying collective nuclear-exciton manifolds. We show an enhanced excitation cross section of the nuclear ensemble which yields superlinear charging, with maximum studied energy density scaling approximately like $n \sqrt{n}$.
Our results provide a route to high-energy-density quantum charging at hard x-ray energies using contemporary x-ray sources and waveguide architectures by identifying nonlinear, collectively enhanced absorption as a key mechanism for nuclear quantum battery operation.
| I am the presenting author | Yes |
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