Quantum mechanics are a little dense for me, but assuming the laws of entropy have not been broken, I think this means a more efficient "concurrent" charging process, as opposed to sequentially charging. Perhaps current "parallel" charging differs in approach to this new process.

> Earlier methods to charge a quantum battery involved a series of charging stages one after the other. However, here, the team instead used a novel quantum effect they call indefinite causal order, or ICO. In the classical realm, causality follows a clear path, meaning that if event A leads to event B, then the possibility of B causing A is excluded.

I don't blame the authors for interpreting this as causality being broken, as most programmers know how difficult causality is to think about once you have concurrent processes in play.