Quasi-Periodic Solutions for Two-Level Systems

Research paper by Guido Gentile

Indexed on: 26 Sep '03Published on: 26 Sep '03Published in: Communications in Mathematical Physics


We consider the Schrödinger equation for a class of two-level atoms in a quasi-periodic external field in the case in which the spacing 2ɛ between the two unperturbed energy levels is small, and we study the problem of finding quasi-periodic solutions of a related generalized Riccati equation. We prove the existence of quasi-periodic solutions of the latter equation for a Cantor set ℰ of values of ɛ around the origin which is of positive Lebesgue measure: such solutions can be obtained from the formal power series by a suitable resummation procedure. The set ℰ can be characterized by requesting infinitely many Diophantine conditions of Mel’nikov type.