Alternative quantization of the Hamiltonian in loop quantum cosmology
By Jinsong Yang, You Ding, Yongge Ma. 2009
148 citations recorded by the source corpus.
Abstract Since there are quantization ambiguities in constructing the Hamiltonian constraint operator in isotropic loop quantum cosmology, it is crucial to check whether the key features of loop quantum cosmology are robust against the ambiguities. In this Letter, we quantize the Lorentz term of the gravitational Hamiltonian constraint in the spatially flat FRW model by two approaches different from that of the Euclidean term. One of the approaches is very similar to the treatment of the Lorentz part of Hamiltonian in loop quantum gravity and hence inherits more features from the full theory. Two symmetric Hamiltonian constraint operators are constructed respectively in the improved scheme. Both of them are shown to have the correct classical limit by the semiclassical analysis. In the loop quantum cosmological model with a massless scalar field, the effective Hamiltonians and Friedmann equations are derived. It turns out that the classical big bang is again replaced by a quantum bounce in both cases. Moreover, there are still great possibilities for the expanding universe to recollapse due to the quantum gravity effect.
Subfields: Astronomy and Astrophysics, Nuclear and High Energy Physics, Statistical and Nonlinear Physics
View Paper: https://www.semanticscholar.org/paper/015374807fa0aee6c047e1ba2e278488a1cb0c8a
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Citations in the corpus
- Introduction to Loop Quantum Cosmology (2011, background): “There is an ambiguity in the chosen symmetric factor ordering and several possibilities have been studied in the literature [12, 21, 127, 144, 154, 203] (see [154] for a detailed comparison between them).”