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MP: Theoretische und Mathematische Grundlagen der Physik

MP 7: Strukturelle Fragen der Quantenfeldtheorie

MP 7.5: Fachvortrag

Donnerstag, 26. März 1998, 15:40–16:00, H45

Infravacuum States and Localization of Sectors in Theories with Massless Particles — •W. Kunhardt — Institut für Theoretische Physik der Universität Göttingen, Bunsenstr. 9, D-37073 Göttingen

One of the difficulties present in models with massless particles consist in the poor localizability of their superselection sectors. As a possible solution to this problem, D. Buchholz pointed out in [1] that charges might become better localized if they are viewed in front of certain appropriate "‘infravacuum"’ background fields and not, as is usually done, in front of the vacuum. Here, we want to verify this mechanism explicitely in the model of a free massless scalar particle. As the infravacuum, we choose a so-called KPR state; this special class of states has been introduced by Kraus et al. in [2] as a mathematical description of infrared clouds. We will show that a certain class of charges can be localized in arbitrary spacelike cones when considered in front of this infravacuum, whereas such a localization is not possible with respect to the vacuum.

[1] D. Buchholz, Commun. Math. Phys. 85 , 49 (1982)

[2] K. Kraus, L. Polley, G. Reents, Ann. Inst. H. Poincaré A 26, 109 (1977)