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arXiv · 2504.00747

Entanglement and Optimal Timing in Discriminating Quantum Dynamical Processes

Massimiliano F. Sacchi
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Abstract

I investigate the problem of optimally discriminating between two open quantum dynamical processes in a single-shot scenario, with the goal of minimizing the error probability of identification. This task involves optimising both the input state -- potentially entangled with an ancillary system that remains isolated from the dynamics -- and the time at which the resulting time-dependent quantum channels, induced by the two distinct dynamical maps, becomes most distinguishable. To illustrate the complexity and richness of this problem, I focus on Pauli dynamical maps and their associated families of time-dependent Pauli channels. I identify a regime in which separable strategies require waiting indefinitely for the dynamics to reach the stationary state, whereas entangled input states enable optimal discrimination at a finite time, with a strict reduction in error probability. These results highlight the crucial interplay between entanglement and timing in enhancing the distinguishability of quantum dynamical processes.

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Massimiliano F. Sacchi. 2025-04-01. Entanglement and Optimal Timing in Discriminating Quantum Dynamical Processes. https://doi.org/10.1016/j.physleta.2025.131199

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