Quantum battery model achieves theoretical speed limit, demonstrates genuine advantage

https://phys.org/news/2025-07-quantum-battery-theoretical-limit-genuine.html

"theoretical model of proposed battery using superconducting circuits... 2 coupled harmonic oscillators: one acts as charger and the other serves as battery. The key ingredient enabling the quantum advantage is an anharmonic interaction between the 2 oscillators during the charging process. This anharmonic coupling allows the system to access non-classical, entangled states that effectively create a shortcut in Hilbert space, enabling faster energy transfer than in classical dynamics"