Note: I was basing my comments on the arXiv preprint https://arxiv.org/abs/2105.12466 https://arxiv.org/abs/2105.12466 "Indefinite Causal Order in Quantum Batte

Note: I was basing my comments on the arXiv preprint https://arxiv.org/abs/2105.12466 https://arxiv.org/abs/2105.12466 "Indefinite Causal Order in Quantum Batteries", which I assumed was the preprint for the PRL paper. It's conceivable that it's not... certainly substantial rewrites have occurred (the title and abstract have changed, and there's an additional author, though the gist looks the same).