{ital U} duality and symplectic formulation of dilaton-axion gravity
- International Centre for Theoretical Physics, Trieste 34100 (Italy)
- Department of Theoretical Physics, Moscow State University, Moscow 119899 (Russia)
We study a bosonic four-dimensional effective action corresponding to the heterotic string compactified on a six-torus (dilaton-axion gravity with one vector field) on a curved space-time manifold possessing a timelike Killing vector field. Previously the existence of the SO(2,3){approximately}Sp(4,{ital R}) global symmetry ({ital U} duality) as well as the symmetric space property of the corresponding {sigma} model have been established following the Neugebauer-Kramer approach. Here we present an explicit form of the Sp(4,{ital R}) generators in terms of coset variables and construct a representation of the coset in terms of the physical target space coordinates. A complex symmetric 2{times}2 matrix {ital Z} ({open_quote}{open_quote}matrix dilaton-axion{close_quote}{close_quote}) is then introduced for which {ital U} duality takes the matrix-valued SL(2,{ital R}) form. In terms of this matrix the theory is further presented as a K{umlt a}hler {sigma} model. This leads to a more economic 2{times}2 formulation suggesting some new solution-generating techniques. A new solution (corresponding to constant Im{ital Z}) is obtained which describes the system of point massless magnetic monopoles endowed with axion charges. In such a system mutual magnetic repulsion is exactly balanced by axion attraction so that the resulting space-time is locally flat but possesses multiple Taub-NUT singularities. {copyright} {ital 1996 The American Physical Society.}
- OSTI ID:
- 286242
- Journal Information:
- Physical Review, D, Vol. 54, Issue 2; Other Information: PBD: Jul 1996
- Country of Publication:
- United States
- Language:
- English
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