Star Topology Optimizes the Charging Power of Quantum Batteries

TL;DR

This paper demonstrates that a star topology in quantum batteries maximizes early charging power, highlighting the importance of internal interaction architecture for optimizing energy transfer speed.

Contribution

It proves that star topology maximizes early time charging power in fermionic quantum batteries, supported by numerical analysis and benchmarks.

Findings

Star topology maximizes early charging power.

Numerical validation for graphs with up to 7 vertices.

Hub-and-spoke designs are recommended for scalable quantum batteries.

Abstract

Quantum batteries are quantum systems that store energy and deliver it on demand, and their practical value hinges on how fast they can be charged. While collective charging protocols and global control are known to enhance charging power, it remains unclear how the battery's internal interaction architecture itself constrains performance. Here we study interacting fermionic batteries whose internal couplings are encoded by a graph adjacency matrix, charged via a simple interaction with an external fermionic device. We prove that the star topology maximises the early time charging power, which proxies the maximal average power - a widely used quantum battery quality metric. We substantiate the result numerically by an exhaustive sweep over all graphs with $N\leq 7$ vertices and by benchmarks against random graph ensembles at larger $N$. Our findings shed light on architecture as a controllable knob for fast charging and motivate hub-and-spoke designs in scalable quantum-battery platforms.