Local Inaccessibility of Random Classical Information and Their Implications in the Change Point Problem

TL;DR

This paper introduces a new framework for input-dependent local quantum state discrimination, revealing entanglement presence and impacting quantum change point estimation, with implications for local information retrieval.

Contribution

It proposes a generalized input-dependent discrimination framework, linking impossibility results to entanglement detection and exploring implications for quantum change point problems.

Findings

Impossibility of local random authentication certifies entanglement.

The framework distinguishes between orthogonal quantum states.

Results have implications for quantum change point estimation.

Abstract

Discrimination of quantum states under local operations and classical communication (LOCC) is an intriguing question in the context of local retrieval of classical information, encoded in the multipartite quantum systems. All the local quantum state discrimination premises, considered so far, mimic a basic communication set-up, where the spatially separated decoding devices are independent of any additional input. Here, exploring a generalized communication scenario, we introduce a framework for input-dependent local quantum state discrimination, which we call local random authentication (LRA). We report that impossibility of LRA certifies the presence of entangled states in the ensemble, a feature absent from erstwhile nonlocality arguments based on local state discrimination. Additionally, we explore the salient features of this state discrimination prototype for arbitrary set of orthogonal quantum states and compare them with the traditional notion of local quantum state discrimination. Finally, our results reveal a fundamental information-theoretic implications in the local estimation of quantum change point problems.