2025/12/15 by Davide Desio, Robert Seiringer, Desio, Davide +1
Mathematics · #Random Matrices and Applications #Stochastic processes and statistical mechanics #Spectral Theory in Mathematical Physics
paper · pdf · doi:10.1007/s11005-026-02107-2
Abstract 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 [14] using a probabilistic approach via Wiener integrals.