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Emergence Of Stringlike Physics From Lorentz Invariance In Loop Quantum Gravity, Rodolfo Gambini, Jorge Pullin
Emergence Of Stringlike Physics From Lorentz Invariance In Loop Quantum Gravity, Rodolfo Gambini, Jorge Pullin
Faculty Publications
We consider a quantum field theory on a spherically symmetric quantum spacetime described by loop quantum gravity. The spin network description of spacetime in such a theory leads to equations for the quantum field that are discrete. We show that to avoid significant violations of Lorentz invariance, one needs to consider specific nonlocal interactions in the quantum field theory similar to those that appear in string theory. This is the first sign that loop quantum gravity places restrictions on the type of matter considered, and points to a connection with string theory physics.
Hawking Radiation From A Spherical Loop Quantum Gravity Black Hole, Rodolfo Gambini, Jorge Pullin
Hawking Radiation From A Spherical Loop Quantum Gravity Black Hole, Rodolfo Gambini, Jorge Pullin
Faculty Publications
We introduce quantum field theory on quantum space-times techniques to characterize the quantum vacua as a first step toward studying black hole evaporation in spherical symmetry in loop quantum gravity and compute the Hawking radiation. We use as quantum space-time the recently introduced exact solution of the quantum Einstein equations in vacuum with spherical symmetry and consider a spherically symmetric test scalar field propagating on it. The use of loop quantum gravity techniques in the background space-time naturally regularizes the matter content, solving one of the main obstacles to back-reaction calculations in more traditional treatments. The discreteness of area leads …
Quantum Black Holes In Loop Quantum Gravity, Rodolfo Gambini, Javier Olmedo, Jorge Pullin
Quantum Black Holes In Loop Quantum Gravity, Rodolfo Gambini, Javier Olmedo, Jorge Pullin
Faculty Publications
We study the quantization of spherically symmetric vacuum spacetimes within loop quantum gravity. In particular, we give additional details about our previous work in which we showed that one could complete the quantization of the model and that the singularity inside black holes is resolved. Moreover, we consider an alternative quantization based on a slightly different kinematical Hilbert space. The ambiguity in kinematical spaces stems from how one treats the periodicity of one of the classical variables in these models. The corresponding physical Hilbert spaces solve the diffeomorphism and Hamiltonian constraint but their intrinsic structure is radically different depending on …
Chimera: A Hybrid Approach To Numerical Loop Quantum Cosmology, Peter Diener, Brajesh Gupt, Parampreet Singh
Chimera: A Hybrid Approach To Numerical Loop Quantum Cosmology, Peter Diener, Brajesh Gupt, Parampreet Singh
Faculty Publications
The existence of a quantum bounce in isotropic spacetimes is a key result in loop quantum cosmology (LQC), which has been demonstrated to arise in all the models studied so far. In most of the models, the bounce has been studied using numerical simulations involving states which are sharply peaked and which bounce at volumes much larger than the Planck volume. An important issue is to confirm the existence of the bounce for states which have a wide spread, or which bounce closer to the Planck volume. Numerical simulations with such states demand large computational domains, making them very expensive …
Three Principles For Canonical Quantum Gravity, Rodolfo Gambini, Jorge Pullin
Three Principles For Canonical Quantum Gravity, Rodolfo Gambini, Jorge Pullin
Faculty Publications
We outline three principles that should guide us in the construction of a theory of canonical quantum gravity: (1) diffeomorphism invariance, (2) implementing the proper dynamics and related constraint algebra, (3) local Lorentz invariance. We illustrate each of them with its role in model calculations in loop quantum gravity. © 2013 Elsevier Ltd.