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arXiv:2607.19582

Measurement-Selective Dynamical Symmetry Breaking

Polina Kofman, Elvira Bilokon, Valeriia Bilokon, Denys I. Bondar

quant-phSubmitted Jul 21, 2026• Announced Jul 23, 2026• 0 citations
v1 · Jul 21, 2026v2 · Sep 21, 2026
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Abstract

Continuous measurement is commonly associated with decoherence and the loss of symmetry. Here, we show that weak continuous measurements can instead act selectively: depending on the measured observable, they may either preserve or remove a dynamical relation between initially mirrored states. Using tunneling between the $|+1\rangle$ and $|-1\rangle$ states of a spin-1 system, we demonstrate that measurements of $S_x$ and $S_y$ break the symmetry of the tunneling dynamics in the presence of a longitudinal bias, whereas measurement of $S_z$ leaves it intact. We formulate this behavior within the Lindblad framework, support it with numerical simulations, and reproduce the dissipative dynamics in a two-qubit quantum circuit using Trotterized evolution and stochastic collective rotations. Our results establish continuous measurement as a selective tool for controlling dynamical symmetry in open quantum systems.

Comments
6 pages, 6 figures

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