caa a22 4500 445320265 CHVBK 20180317142701.0 cr unu---uuuuu 170323e20111101xx s 000 0 eng 10.1007/s00023-011-0103-6 doi (NATIONALLICENCE)springer-10.1007/s00023-011-0103-6 Abdesselam Abdelmalek Department of Mathematics, University of Virginia, P. O. Box 400137, 22904-4137, Charlottesville, VA, USA aut The Ground State Energy of the Massless Spin-Boson Model [Elektronische Daten] [Abdelmalek Abdesselam] We provide an explicit combinatorial expansion for the ground state energy of the massless spin-Boson model as a power series in the coupling parameter. Our method uses the technique of cluster expansion in constructive quantum field theory and takes as a starting point the functional integral representation and its reduction to an Ising model on the real line with long range interactions. We prove the analyticity of our expansion and provide an explicit lower bound on the radius of convergence. We do not need multiscale nor renormalization group analysis. A connection to the loop-erased random walk is indicated. Springer Basel AG, 2011 Annales Henri Poincaré SP Birkhäuser Verlag Basel 12/7(2011-11-01), 1321-1347 1424-0637 12:7<1321 2011 12 23 https://doi.org/10.1007/s00023-011-0103-6 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/s00023-011-0103-6 text/html Onlinezugriff via DOI NATIONALLICENCE 100 1- Abdesselam Abdelmalek Department of Mathematics, University of Virginia, P. O. Box 400137, 22904-4137, Charlottesville, VA, USA aut NATIONALLICENCE 773 0- Annales Henri Poincaré SP Birkhäuser Verlag Basel 12/7(2011-11-01), 1321-1347 1424-0637 12:7<1321 2011 12 23 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer