Horizon Entropy from Quantum Gravity Condensates
Abstract
We construct condensate states encoding the continuum spherically symmetric quantum geometry of a horizon in full quantum gravity, i.e., without any classical symmetry reduction, in the group field theory formalism. Tracing over the bulk degrees of freedom, we show how the resulting reduced density matrix manifestly exhibits a holographic behavior. We derive a complete orthonormal basis of eigenstates for the reduced density matrix of the horizon and use it to compute the horizon entanglement entropy. By imposing consistency with the horizon boundary conditions and semiclassical thermodynamical properties, we recover the BekensteinHawking entropy formula for any value of the Immirzi parameter. Our analysis supports the equivalence between the von Neumann (entanglement) entropy interpretation and the Boltzmann (statistical) one.
 Publication:

Physical Review Letters
 Pub Date:
 May 2016
 DOI:
 10.1103/PhysRevLett.116.211301
 arXiv:
 arXiv:1510.06991
 Bibcode:
 2016PhRvL.116u1301O
 Keywords:

 General Relativity and Quantum Cosmology
 EPrint:
 6 pages