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Spherically Symmetric Loop Quantum Gravity: Analysis Of Improved Dynamics, Rodolfo Gambini, Javier Olmedo, Jorge Pullin
Spherically Symmetric Loop Quantum Gravity: Analysis Of Improved Dynamics, Rodolfo Gambini, Javier Olmedo, Jorge Pullin
Faculty Publications
We study the 'improved dynamics' for the treatment of spherically symmetric space-times in loop quantum gravity introduced by Chiou et al in analogy with the one that has been constructed by Ashtekar, Pawlowski and Singh for the homogeneous space-times. In this dynamics the polymerization parameter is a well motivated function of the dynamical variables, reflecting the fact that the quantum of area depends on them. Contrary to the homogeneous case, its implementation does not trigger undesirable physical properties. We identify semiclassical physical states in the quantum theory and derive the corresponding effective semiclassical metrics. We then discuss some of their …
Axisymmetric Gravity In Real Ashtekar Variables: The Quantum Theory, Rodolfo Gambini, Esteban Mato, Jorge Pullin
Axisymmetric Gravity In Real Ashtekar Variables: The Quantum Theory, Rodolfo Gambini, Esteban Mato, Jorge Pullin
Faculty Publications
In a previous paper we formulated axisymmetric general relativity in terms of real Ashtekar-Barbero variables. Here we proceed to quantize the theory. We are able to implement Thiemann's version of the Hamiltonian constraint. This provides a 2 + 1 dimensional arena to test ideas for the dynamics of quantum gravity and opens the possibility of quantum studies of rotating black hole spacetimes.
Gauge-Invariant Bounce From Loop Quantum Gravity, Klaus Liegener, Parampreet Singh
Gauge-Invariant Bounce From Loop Quantum Gravity, Klaus Liegener, Parampreet Singh
Faculty Publications
We present a gauge-invariant treatment of singularity resolution using loop quantum gravity techniques with respect to local SU(2) transformations. Our analysis reveals many novel features of quantum geometry which were till now hidden in models based on non-gauge-invariant discretizations. Quantum geometric effects resolve the big bang singularity replacing it with a non-singular bounce when spacetime curvature reaches Planckian value. The bounce is found to be generically asymmetric in the sense that pre-bounce and post-bounce branches are not mirrored to each other and effective constants, such as Newton's constant, are rescaled across the bounce. Furthermore, in the vicinity of the bounce, …