English

Decoherent histories with(out) objectivity in a (broken) apparatus

Quantum Physics 2026-03-23 v4 Statistical Mechanics

Abstract

We characterize monitored quantum dynamics in a solvable model exhibiting a phase transition between a measurement apparatus and a scrambler. We show that approximate decoherent histories emerge in both phases with respect to a coarse-grained extensive observable. However, the apparatus phase, where quantum Darwinism emerges, is distinguished by the non-ergodicity of the histories and their correlation with the measured qubit, which selects an ensemble of preferred pointer states. Our results demonstrate a clear distinction between two notions of classicality, decoherent histories and environment-induced decoherence.

Keywords

Cite

@article{arxiv.2508.16482,
  title  = {Decoherent histories with(out) objectivity in a (broken) apparatus},
  author = {Benoît Ferté and Davide Farci and Xiangyu Cao},
  journal= {arXiv preprint arXiv:2508.16482},
  year   = {2026}
}

Comments

13 pages, 4 figures; v3: approximately matching published version