Holographic thought experiments
- Physics Department, University of California, Santa Barbara, Santa Barbara, California 93106 (United States)
The Hamiltonian of classical anti-de Sitter gravity is a pure boundary term on-shell. If this remains true in nonperturbative quantum gravity then (i) boundary observables will evolve unitarily in time and (ii) the algebra of boundary observables is the same at all times. In particular, information available at the boundary at any one time t{sub 1} remains available at any other time t{sub 2}. Since there is also a sense in which the equations of motion propagate information into the bulk, these observations raise what may appear to be potential paradoxes concerning simultaneous (or spacelike separated) measurements of noncommuting observables, one at the asymptotic boundary and one in the interior. We argue that such potentially paradoxical settings always involve a breakdown of semiclassical gravity. In particular, we present evidence that making accurate holographic measurements over short time scales radically alters the familiar notion of causality. We also describe certain less intrinsically paradoxical settings which illustrate the above boundary unitarity and render the notion more concrete.
- OSTI ID:
- 21259824
- Journal Information:
- Physical Review. D, Particles Fields, Vol. 79, Issue 2; Other Information: DOI: 10.1103/PhysRevD.79.024029; (c) 2009 The American Physical Society; Country of input: International Atomic Energy Agency (IAEA); ISSN 0556-2821
- Country of Publication:
- United States
- Language:
- English
Similar Records
Light-Front Holographic QCD
Black holes and beyond