Comment on "Integrability of the Rabi model"
arXiv:1205.3139
Abstract
In his recent letter, Braak suggested that a regular spectrum of the Rabi model was given by the zeros of a transcendental function (cf Eqs. (3)-(5) of Ref. [1]) and highlighted the role of the discrete -symmetry, or parity, in determining . We show here to the contrary that one can define a transcendental function and obtain the regular spectrum of the Rabi model as the zeros of (see Fig. 1) without ever making use of the underlying -symmetry of the model.
1 page, 1 figure - a couple of text typos corrected; no change in formulas