No-Go Theorem for Quasiparticle BEC in the Spin-Boson Model
Mathematical Physics
2026-05-07 v3 math.MP
Abstract
We analyze the possibility of Bose-Einstein condensation (BEC) at finite temperature in the spin-boson model within the frameworks of functional integral representations and the resolvent algebra. Because a sesquilinear form arising from the zero mode appears, analogous to the case of the free Bose gas, a BEC-type component is also formally present in the spin-boson model. However, according to arxiv:1207.4621, quasiparticles do not undergo BEC, so an argument is needed to exclude this possibility. In particular, for moderate equilibrium states defined by following the formulation of that paper, a no-go theorem for BEC is obtained.
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Cite
@article{arxiv.2604.27904,
title = {No-Go Theorem for Quasiparticle BEC in the Spin-Boson Model},
author = {Yoshitsugu Sekine},
journal= {arXiv preprint arXiv:2604.27904},
year = {2026}
}
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28 pages