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Algorithmic approach to Cosmological Coherent State Expectation Values in LQG

Authors :
Liegener, Klaus
Rudnicki, Łukasz
Source :
Class. Quantum Grav. 38, 205001 (2021)
Publication Year :
2020

Abstract

In the lattice approach to Loop Quantum Gravity on a fixed graph computations tend to be involved and are rarely analytically manageable. But, when interested in the expectation values of coherent states on the lattice which are sharply peaked on isotropic, flat cosmology several simplifications are possible which reduce the computational effort. We present a step-by-step algorithm resulting in an analytical expression including up to first order corrections in the spread of the state. The algorithm is developed in such a way that it makes the computation straightforward and easy to be implementable in programming languages such as Mathematica. Exemplarily, we demonstrate how the algorithm streamlines the road to obtain the expectation value of the euclidean part of the scalar constraint and as a consistency check perform the analytic computation as well. To showcase further applications of the algorithm, we investigate the fate of the effective dynamics program custom in Loop Cosmology and find that the next-to-leading order corrections can {\it not} be used as corrections for an effective Hamiltonian.<br />Comment: 33 pages; This paper summarizes the results announced at Loops'19 Conference [http://gravity.psu.edu/events/loops19/index-loops19.shtml]. First draft - minor typos can still be found

Details

Database :
arXiv
Journal :
Class. Quantum Grav. 38, 205001 (2021)
Publication Type :
Report
Accession number :
edsarx.2012.07813
Document Type :
Working Paper
Full Text :
https://doi.org/10.1088/1361-6382/ac226f