Holography, SL(2,R) symmetry, Virasoro algebra and all that in Rindler spacetime

It is shown that it is possible to define quantum field theory of a massless scalar free field on the event horizon of a 2D-Rindler spacetime. Free quantum field theory on the horizon enjoys diffeomorfism invariance and turns out to be unitarily and algebraically equivalent to the analogous theory of a scalar field prapogating inside Rindler spacetime, nomatter the value of the mass of the field in the bulk. More precisely, there exist a unique transformation that realizes the bulk-boundary correspondence upon an appropriate choice for Fock representation spaces. Secondly, the found correspondence is a subcase of an analogous algebraic correspondence described by the injective homomorphisms of the abstract algebras of observables generated by abstract quantum free-field operators. These field operators are smeared with suitable test functions in the bulk and exact 1-forms on the horizon. In this sense the correspondence is independent from the chosen vacua. It is proven that, under that correspondence the 'hidden' SL(2,R) quantum symmetry found in a previous work gets a clear geometric meaning, it being associated with a group of diffeomorphisms of the horizon itself. Finally it is found that there is a possible enlargement of the quantum symmetry on the horizon to a quantum Virasoro symmetry associated with vector fields on the event horizon.