• Accepted Paper

Dissipation of Spekkens’ generalized contextuality under decoherence: The classical limit

Enrico Bozzetto and Jonte R. Hance

Phys. Rev. A - Accepted 5 November, 2026

DOI: https://doi.org/10.1103/ng5j-lw7n

Abstract

When does a decohering quantum system become classical? Generalised noncontextuality gives one criterion, for scenarios rich enough in preparations: a system is classical once its statistics admit an underlying model in which operationally indistinguishable procedures are physically identical. Where it crosses depends not on the state and channel alone but on which preparations, transformations and measurements the experiment offers, and if every measurement is allowed there is no crossing. For any pairwise unbiased bases in any dimension, given preparations holding their eigenstates and surrounding the maximally mixed state, the question reduces to a finite linear program; for a qudit of odd prime dimension d restricted to the stabiliser subtheory, with one depolarised magic state, we solve it in closed form. With preparations and measurements alone the qutrit strange state is classical at zero noise; with the Clifford gates added, each channel represented once, it crosses at 3/5; and with a random gate represented, as Spekkens’ treatment asks, by the matching mixture of stochastic maps, at 3/4. A Clifford orbit of assignments supports such a representation only if it has d2 members, leaving, in every odd prime dimension, only Gross’s discrete Wigner function: the crossing sits where it stops being negative.

Export citation

Export citation

Choose format for download:

Download Citation

If the author has provided any supplemental materials with this article they will be available upon publication of the version of record.

Sign In to Your Journals Account

Filter

Filter

Article Lookup

Enter a citation