Dyson expansion for form-bounded perturbations, and applications to the polaron problem

Fuente: arXiv
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Main Authors: Desio, Davide, Seiringer, Robert
Format: Preprint
Published: 2025
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author Desio, Davide
Seiringer, Robert
author_facet Desio, Davide
Seiringer, Robert
contents We present an abstract Dyson expansion for perturbations that are merely relatively form-bounded, and apply it to the polaron problem. For a large class of polaron-type models, including the Fröhlich and Nelson models, we prove that the vacuum expectation value of the heat semi-group is a completely monotone function of the square of the total momentum. Consequently, the ground state energy is a concave function of the square of the momentum, a result recently proved for the Fröhlich model in \cite{polzer} using a probabilistic approach via Wiener integrals.
format Preprint
id arxiv_https___arxiv_org_abs_2512_13443
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Dyson expansion for form-bounded perturbations, and applications to the polaron problem
Desio, Davide
Seiringer, Robert
Mathematical Physics
We present an abstract Dyson expansion for perturbations that are merely relatively form-bounded, and apply it to the polaron problem. For a large class of polaron-type models, including the Fröhlich and Nelson models, we prove that the vacuum expectation value of the heat semi-group is a completely monotone function of the square of the total momentum. Consequently, the ground state energy is a concave function of the square of the momentum, a result recently proved for the Fröhlich model in \cite{polzer} using a probabilistic approach via Wiener integrals.
title Dyson expansion for form-bounded perturbations, and applications to the polaron problem
topic Mathematical Physics
url https://arxiv.org/abs/2512.13443