For an extremal invariant state ω of a weakly asymptotically abelian dynamical system we prove that the corresponding energy spectrum is either one-sided or the whole reals, or a periodic subgroup. The latter case implies abelianness of the algebra in the representation generated by ω.
|Original language||English (US)|
|Number of pages||4|
|Journal||Communications in Mathematical Physics|
|State||Published - Feb 1977|
ASJC Scopus subject areas
- Statistical and Nonlinear Physics
- Mathematical Physics