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Résumé |
Two-dimensional quantum fields theories rather universally contain an interesting operator built from the stress tensor, called ``TTbar''. Although this operator is irrelevant, adding it to the action generates a new family of theories in a controlled way. For the particular case of conformal field theories with an Anti-de Sitter holographic dual, it has been proposed that the TTbar-deformed theories correspond to the theories ``living'' on hypersurfaces of fixed radius in AdS. We will use the variational principle in the CFT to derive mixed boundary conditions for the dual metric at large N. This confirms the conjecture for pure gravity and for a particular sign of the deformation parameter, but it requires modification when matter is present. The asymptotic symmetries of the gravitational theory with mixed boundary conditions form two Virasoro algebras, the generators of which are state-dependent but the central charge remains unchanged. |
