Moduli integrals and ground ring in minimal liouville gravity
A. A. Belavin, A. B. Zamolodchikov*
L. D. Landau Institute for Theoretical Physics RAS, 142432 Chernogolovka, Moscov reg., Russia
*Laboratoire de Physique Théorique et Astroparticules, UniversitéMontpelier II, Pl.E. Bataillon, 34095 Montpelier, France
PACS: 11.25.Hf
Abstract
Straightforward evaluation of the correlation functions
in 2D minimal gravity requires integration over the moduli space.
For degenerate fields the Liouville higher equations of motion
allow to turn the integrand to a derivative and thus to reduce it
to the boundary terms plus so-called curvature contribution. The
last is directly related to the expectation value of the
corresponding ground ring element. We use the operator product
expansion technique to reproduce the ground ring construction
explicitly in terms of the (generalized) minimal matter and
Liouville degenerate fields. The action of the ground ring on the
generic primary fields is evaluated explicitly. This permits us to
construct directly the ground ring algebra. Detailed analysis of
the ground ring mechanism is helpful in the understanding of the
boundary terms and their evaluation.