This is an unreviewed preprint posted to arXiv and has not yet undergone peer review. The authors examine a quantum battery built from a dimerized spin chain described by the Su-Schrieffer-Heeger (SSH) model, asking a pointed question that existing theory leaves open: when energy can only enter and leave through a single physical port, how much of the stored work is actually accessible there, and does topological structure help?
Using an exact mapping to free fermions, the paper derives a bound on extractable work for any number-conserving quadratic protocol operating at one boundary. The key criterion they identify is occupation-based: a single-particle mode must hold more than half an excitation for the load to gain any extractable work at all. The authors claim that resonant collision-based charging preferentially fills the topological edge mode above this threshold, and that a single boundary pulse subsequently delivers 98.6% of the maximum allowed load work under representative parameters. The trivial phase, charged under the same six-collision protocol, leaves the load passive — unable to extract useful work at the boundary.
The paper also reports that the topological advantage persists under hopping disorder, which respects chiral symmetry, but that on-site disorder — which breaks that symmetry — renders a finite fraction of loads passive. The authors frame the result as a separation of roles: topology provides a localized access channel at the boundary, while spectral matching and symmetry determine whether stored energy is convertible into usable local work. These claims await independent verification through peer review.