39 research outputs found
potential from AdS-CFT relation at : Dependence on orientation in internal space and higher curvature corrections
Within the classical approximation we calculate the static
potential via the AdS/CFT relation for nonzero temperature and arbitrary
internal orientation of the quarks. We use a higher order curvature corrected
target space background. For timelike Wilson loops there arises a critical line
in the orientation-distance plane which is shifted to larger distances relative
to the calculation with uncorrected background. Beyond that line there is no
-force. The overall vanishing of the force for antipodal orientation
known from zero tempera ture remains valid. The spacelike Wilson loops yield a
string tension for a (2+1)-dimensional gauge theory, independent of the
relative internal orientation, but sensitive to the background correction.Comment: Used background has been adapted to hep-th/9808126 and revised
version of hep-th/9805156, slightly changed comment on 1/L ter
Two and three-point functions in Liouville theory
Based on our generalization of the Goulian-Li continuation in the power of
the 2D cosmological term we construct the two and three-point correlation
functions for Liouville exponentials with generic real coefficients. As a
strong argument in favour of the procedure we prove the Liouville equation of
motion on the level of three-point functions. The analytical structure of the
correlation functions as well as some of its consequences for string theory are
discussed. This includes a conjecture on the mass shell condition for
excitations of noncritical strings. We also make a comment concerning the
correlation functions of the Liouville field itself.Comment: 15 pages, Latex, Revised version: A sign error in formula (50) is
correcte
On T-duality for open strings in general abelian and nonabelian gauge field backgrounds
We discuss T-duality for open strings in general background fields both in
the functional integral formulation as well as in the language of canonical
transformations. The Dirichlet boundary condition in the dual theory has to be
treated as a constraint on the functional integration. Furthermore, we give
meaning to the notion of matrix valued string end point position in the
presence of nonabelian gauge field background.Comment: 10 pages, Latex, an inconsistency of the notation in section 3 is
removed, 2 references adde
Remarks on T-duality for open strings
This contribution gives in sigma-model language a short review of recent work
on T-duality for open strings in the presence of abelian or non-abelian gauge
fields. Furthermore, it adds a critical discussion of the relation between RG
beta-functions and the Born-Infeld action in the case of a string coupled to a
D-brane.Comment: 7 pages, LATEX, requires esprc2.sty (included in uu-file