Local asymmetry in interference as a probe of quantum probability

TL;DR

This paper proposes that local asymmetries in interference fringes can serve as a direct test of the Born rule in quantum mechanics, revealing subtle deviations without altering the standard wave dynamics.

Contribution

It introduces a minimal deformation of quantum probability that produces a universal, observable asymmetry in interference patterns, providing a new way to test the foundations of quantum theory.

Findings

Asymmetry manifests as cubic skewness in local intensity profiles.

The effect preserves linear Schrödinger dynamics and fringe positions.

The signature is robust against experimental noise and scale insensitive.

Abstract

Quantum interference provides one of the most sensitive probes of quantum mechanics. While linear superposition fixes the positions and quadratic curvature of interference fringes, it remains unclear whether the probabilistic postulate itself, the Born rule, can be tested through finer, local features of interference patterns. Here we show that a minimal deformation of quantum probability gives rise to a robust and symmetry-protected signature: a left-right asymmetry in the local shape of interference fringes. Remarkably, this effect leaves the linear Schr\"odinger dynamics intact and does not shift fringe positions or modify their quadratic curvature. Instead, it appears exclusively as a cubic skewness of local intensity profiles, providing a clean and falsifiable observable. We demonstrate this behavior within a controlled realization that preserves linear dynamics while minimally deforming the probabilistic assignment. The resulting signature is universal, scale insensitive, and cannot be mimicked by conventional sources of experimental noise. Our results identify local asymmetry in interference as a direct probe of quantum probability itself, suggesting that features often regarded as removable imperfections may encode fundamental information beyond fringe positions and widths.