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"Reversibility of quantum resources through probabilistic protocols" (2024) https://www.nature.com/articles/s41467-024-47243-2 https://www.nature.com/articles/s
by westurner 2y ago
"Reversibility of quantum resources through probabilistic protocols" (2024) https://www.nature.com/articles/s41467-024-47243-2 https://www.nature.com/articles/s41467-024-47243-2 :
> Abstract: Among the most fundamental questions in the manipulation of quantum resources such as entanglement is the possibility of reversibly transforming all resource states. The key consequence of this would be the identification of a unique entropic resource measure that exactly quantifies the limits of achievable transformation rates. Remarkably, previous results claimed that such asymptotic reversibility holds true in very general settings; however, recently those findings have been found to be incomplete, casting doubt on the conjecture. Here we show that it is indeed possible to reversibly interconvert all states in general quantum resource theories, as long as one allows protocols that may only succeed probabilistically. Although such transformations have some chance of failure, we show that their success probability can be ensured to be bounded away from zero, even in the asymptotic limit of infinitely many manipulated copies. As in previously conjectured approaches, the achievability here is realised through operations that are asymptotically resource non-generating, and we show that this choice is optimal: smaller sets of transformations cannot lead to reversibility. Our methods are based on connecting the transformation rates under probabilistic protocols with strong converse rates for deterministic transformations, which we strengthen into an exact equivalence in the case of entanglement distillation.
- westurner 2y ago> The key consequence of this would be the identification of a unique entropic resource measure that exactly quantifies the limits of achievable transformation rates IIRC I read on Wikipedia one day that Bell's actually says there's like a 60% error rate?(!) Also I don't understand QKD 'repeaters'; to 'store a forward' wave function implies that the transmitted wave state is collapsed, but that's not a MITM if it's keyed and time synchronized? Is there no good way to amplify quantum photonic signal without distorting / transforming it? > smaller sets of transformations cannot lead to reversibility "Thermodynamics of Computations with Absolute Irreversibility, Unidirectional Transitions, and Stochastic Computation Times" (2024) https://journals.aps.org/prx/abstract/10.1103/PhysRevX.14.021026 https://journals.aps.org/prx/abstract/10.1103/PhysRevX.14.02... : - "New work extends the thermodynamic theory of computation" https://phys.org/news/2024-05-thermodynamic-theory.amp https://phys.org/news/2024-05-thermodynamic-theory.amp https://journals.aps.org/prx/abstract/10.1103/PhysRevX.14.021026 https://journals.aps.org/prx/abstract/10.1103/PhysRevX.14.02...