• DOI:10.1007/s00023-011-0103-6
• Corpus ID: 119161955

The Ground State Energy of the Massless Spin-Boson Model

@article{Abdesselam2010TheGS,
  title={The Ground State Energy of the Massless Spin-Boson Model},
  author={Abdelmalek Abdesselam},
  journal={Annales Henri Poincar{\'e}},
  year={2010},
  volume={12},
  pages={1321-1347}
}

• A. Abdesselam
• Published 24 May 2010
• Physics
• Annales Henri Poincaré

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.