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arXiv:0704.3445 · Journal of Mathematical Physics

Lower spectral branches of a spin-boson model

Nicolae Angelescu, R. A. Minlos, Jean Ruiz, Valentin Anatol'evich Zagrebnov

Published Oct 1, 2008• 10 citations
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Abstract

We study the structure of the spectrum of a two-level quantum system weakly coupled to a boson field (spin-boson model). Our analysis allows to avoid the cutoff in the number of bosons, if their spectrum is bounded below by a positive constant. We show that, for small coupling constant, the lower part of the spectrum of the spin-boson Hamiltonian contains (one or two) isolated eigenvalues and (one or two) manifolds of atom +1-boson states indexed by the boson momentum q. The dispersion laws and generalized eigenfunctions of the latter are calculated.

DOI
10.1063/1.2987721

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