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arXiv:2511.06624 · Journal of Physics A Mathematical and Theoretical

No-signalling-projection-invariant Bell inequalities

Soumyadip Patra, Jitendra Prakash, Aaditya Paudel, Peter Bierhorst

quant-phSubmitted Nov 10, 2025• Announced Nov 11, 2025• 0 citations
v1 · Nov 10, 2025v2 · Jul 20, 2026
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Abstract

In this paper, we highlight how any Bell inequality for a configuration involving $n$ parties each performing one of $m$ binary-outcome measurements has a canonical form that is no-signalling-projection invariant. Specifically, the $L^2$-projection of weakly signalling data onto the no-signalling polytope leaves the violation of this canonical Bell inequality unchanged. Our methods allow us to derive a general closed formula for the projection and present a substantially more computationally simple procedure for its evaluation. We also show this can be generalised to non-standard projections of potential interest for certain applications. No-signalling projections serve as a preliminary step before undertaking any device-independent application involving Bell experiment data, such as hypothesis testing against local realism, random number generation and entanglement detection.

Journal reference
J. Phys. A: Math. Theor. 59, 315303 (2026)
DOI
10.1088/1751-8121/ae8d64
Comments
20 pages

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