Stochastic approximate state conversion for entanglement and general quantum resource theories

TL;DR

This paper establishes fundamental limits on the fidelity and probability of approximate quantum state conversions across all resource theories, with specific solutions for entangled states and implications for quantum channel manipulation.

Contribution

It introduces universal bounds on stochastic approximate state conversions, extending to channels and providing exact solutions for certain entangled state transformations.

Findings

Derived bounds on maximal transformation fidelity for given probabilities.

Established upper bounds on asymptotic transformation rates.

Solved specific cases of entangled state conversion via LOCC.

Abstract

Quantum resource theories provide a mathematically rigorous way of understanding the nature of various quantum resources. An important problem in any quantum resource theory is to determine how quantum states can be converted into each other within the physical constraints of the theory. The standard approach to this problem is to study approximate or probabilistic transformations. Here, we investigate the intermediate regime, providing limits on both, the fidelity and the probability of state transformations. We derive limitations on the transformations, which are valid in all quantum resource theories, by providing bounds on the maximal transformation fidelity for a given transformation probability. As an application, we show that these bounds imply an upper bound on the asymptotic rates for various classes of states under probabilistic transformations. We also show that the deterministic version of the single copy bounds can be applied for drawing limitations on the manipulation of quantum channels, which goes beyond the previously known bounds of channel manipulations. Furthermore, we completely solve the question of stochastic-approximate state conversion via local operations and classical communication in the following two cases: (i) Both initial and target states are pure bipartite entangled states of arbitrary dimensions. (ii) The target state is a two-qubit entangled state and the initial state is a pure bipartite state.