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arXiv · 2603.08618

Bias in Local Spin Measurements from Deformed Symmetries

Michele Arzano·Goffredo Chirco·Jerzy Kowalski-Glikman
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Abstract

We study local spin measurements on bipartite singlet states when rotational symmetry is described by a quantum group rather than an ordinary Lie group. Although the fundamental spin-1/2 representation has the usual one-particle action on states, the non-trivial coproduct selects a deformed analogue of the Bell singlet state. We show that conventional tensor-factor measurements on this invariant singlet lead to deformation-dependent one-site outcome statistics. We then compare this standard-local prescription with a braided-local one, obtained by dressing local observables with the R-matrix and using the corresponding braided inner product. The braided observables are covariant under the Hopf adjoint action, but define a distinct measurement structure and lead to the reciprocal bias on the deformed singlet state.

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Michele Arzano, Goffredo Chirco, Jerzy Kowalski-Glikman. 2026-03-09. Bias in Local Spin Measurements from Deformed Symmetries. https://arxiv.org/abs/2603.08618

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