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arXiv · 2509.17332

Quantum coherence induced by magnons

V. C. Vieira·F. M. de Paula
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Abstract

We analyze quantum coherence generated by non-interacting magnons in a ferromagnetic spin chain described by the isotropic Heisenberg model. The exact expression derived for the reduced density operator of an arbitrary subsystem reveals that single-site coherence vanishes, while maximal coherence arises in a pure single-mode magnon state. Remarkably, this maximum depends solely on the number of coherently superposed microstates. Based on this property, we introduce coherence-based definitions of entropy, temperature, and heat capacity, establishing a formal analogy with standard thermodynamic quantities.

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V. C. Vieira, F. M. de Paula. 2025-09-22. Quantum coherence induced by magnons. https://arxiv.org/abs/2509.17332

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