The crossed product construction is used to control in some examples the asymptotic behaviour of time evolution. How invariant states on a small algebra can be extended to invariant states on a larger algebra reduces to solving an eigenvalue problem. In some cases (the irrational rotation algebra) this eigenvalue problem has only trivial solutions and by reduction of the subalgebra control on all invariant states can be found.
@article{bwmeta1.element.bwnjournal-article-bcpv43i1p331bwm, author = {Narnhofer, Heide}, title = {Control on weak asymptotic abelianness with the help of the crossed product construction}, journal = {Banach Center Publications}, volume = {43}, year = {1998}, pages = {331-339}, zbl = {0937.46060}, language = {en}, url = {http://dml.mathdoc.fr/item/bwmeta1.element.bwnjournal-article-bcpv43i1p331bwm} }
Narnhofer, Heide. Control on weak asymptotic abelianness with the help of the crossed product construction. Banach Center Publications, Tome 43 (1998) pp. 331-339. http://gdmltest.u-ga.fr/item/bwmeta1.element.bwnjournal-article-bcpv43i1p331bwm/
[000] [1] F. Acerbi, G. Morchio and F. Strocchi, Lett. Math. Phys. 26 (1992), 13; Lett. Math. Phys. 27 (1993), 1.
[001] [2] H. Araki and T. Matsui, Commun. Math. Phys. 101 (1985) 213.
[002] [3] F. Benatti, H. Narnhofer and G. L. Sewell, Lett. Math. Phys. 21 (1991) 157.
[003] [4] M. Born and N. Nagendra-Nath, Proc. Ind. Acad. Sci. 3 (1936) 318.
[004] [5] A.L. Carey and S. N. M. Ruijsenaars, Acta Appl. Math. 10 (1987) 1.
[005] [6] R. Haag, D. Kastler and E. B. Trych-Pohlmeyer, Commun. Math. Phys. 56 (1977) 213.
[006] [7] N. Ilieva and H. Narnhofer, Sitzungsber. Österr. Akad. d. Wiss., Abt. II, 205 (1996) 13.
[007] [8] P. Jordan, Z. Phys. 93 (1935) 464; 98 (1936) 759; 99 (1936) 109.
[008] [9] D.C. Mattis and E. Lieb, J. Math. Phys. 6 (1965) 304.
[009] [0] H. Narnhofer and W. Thirring, Phys. Rev. A 26/6 (1982) 3646.
[010] [11] H. Narnhofer and W. Thirring, Spontaneously Broken Symmetry, Vienna preprint (1997).
[011] [12] H. Narnhofer, Properties of Automorphisms on the Rotation Algebra, Vienna preprint (1997). | Zbl 0914.46057
[012] [13] F. Riesz and B. Sz-Nagy, Leçons d'analyse fonctionnelle, 6. ed. Gauthier-Villars, Paris, 1972.
[013] [14] D. Ruelle, Statistical Mechanics, Benjamin, New York, 1969.