Non-stabilizerness and violations of CHSH inequalities

arXiv:2504.03351 · quant-ph · Submitted 2025-04-04 · Read on arXiv

quant-ph

Submitted: 2025-04-04

Updated: 2026-09-07

Comments: 24 pages, 6 figures, 2 tables

Journal ref: Quantum 10, 2214 (2026)

DOI: 10.22331/q-2026-09-21-2214

License: http://creativecommons.org/licenses/by/4.0/

The gist: We study quantitatively the interplay between entanglement and non-stabilizer resources in violating the CHSH inequalities.

Terminology

Abstract

We study quantitatively the interplay between entanglement and non-stabilizer resources in violating the CHSH inequalities. We show that, while non-stabilizer resources are necessary, they must have a specific structure, namely they need to be both asymmetric and (surprisingly) local. We employ stabilizer entropy (SE) to quantify the non-stabilizer resources involved and the probability of violation given the resources. We show how spectral quantities related to the flatness of entanglement spectrum and its relationship with non-local SE affect the CHSH inequality. Finally, we utilize these results - together with tools from representation theory - to construct a systematic way of building ensembles of states with higher probability of violation.

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