{ "id": "1611.08538", "version": "v1", "published": "2016-11-25T18:03:21.000Z", "updated": "2016-11-25T18:03:21.000Z", "title": "Mass Renormlization in the Nelson Model", "authors": [ "Fumio Hiroshima", "Susumu Osawa" ], "categories": [ "math-ph", "math.MP" ], "abstract": "The asymptotic behavior of the effective mass $m_{\\rm eff}(\\Lambda)$ of the so-called Nelson model in quantum field theory is considered, where $\\Lambda$ is an ultraviolet cutoff parameter of the model. Let $m$ be the bare mass of the model. It is shown that for sufficiently small coupling constant $|\\alpha|$ of the model, $m_{{\\rm eff}}(\\Lambda)/m$ can be expanded as $m_{{\\rm eff}}(\\Lambda)/m= 1+\\sum_{n=1}^\\infty a_n(\\Lambda) \\alpha^{2n}$. A physical folklore is that $a_n(\\Lambda)\\sim [\\log \\Lambda]^{(n-1)}$ as $\\Lambda\\to \\infty$. It is rigorously shown that $$0<\\lim_{\\Lambda\\to\\infty}a_1(\\Lambda)