TUW-00-16

Two-Dilaton Theories in Two Dimensions








D. Grumiller, D. Hofmann, W. Kummer,

Institut für Theoretische Physik
Technische Universität Wien
Wiedner Hauptstr. 8-10, A-1040 Wien, Austria

Abstract:

Dimensional reduction of generalized gravity theories or string theories generically yields dilaton fields in the lower dimensional effective theory. Thus at the level of D=4 theories and cosmology many models contain more than just one scalar field (e.g. inflaton, Higgs, quintessence). Our present work is restricted to two-dimensional gravity theories with only two dilatons which nevertheless allow a large class of physical applications.
The notions of factorizability, simplicity and conformal simplicity, Einstein form and Jordan form are the basis of a general classification. We show that practically all physically motivated models belong either to the class of factorizable simple theories (e.g. dimensionally reduced gravity, bosonic string) or to factorizable conformally simple theories (e.g. spherically reduced scalar tensor theories, spherically reduced Kaluza-Klein theory). For these theories a first order formulation can be constructed in a straightforward way. As a consequence an absolute conservation law can be established.

PACS numbers: 04.50.th, 04.60.Kz, 11.30.-j