scholarly journals Solvable loop quantum cosmology: Domain of the volume observable and semiclassical states

2019 ◽  
Vol 99 (4) ◽  
Author(s):  
Mercedes Martín-Benito ◽  
Rita B. Neves
Keyword(s):  
Quantum Cosmology ◽  
Loop Quantum Cosmology ◽  
Semiclassical States

scholarly journals The Effect of a Positive Cosmological Constant on the Bounce of Loop Quantum Cosmology

Mathematics ◽  
2020 ◽  
Vol 8 (2) ◽  
pp. 186
Author(s):  
Mercedes Martín-Benito ◽  
Rita B. Neves
Keyword(s):  
Scalar Field ◽  
Cosmological Constant ◽  
Quantum Cosmology ◽  
Quantum Dynamics ◽  
Solvable Model ◽  
Massless Scalar ◽  
Loop Quantum Cosmology ◽  
Massless Scalar Field ◽  
Positive Cosmological Constant ◽  
Semiclassical States

We provide an analytical solution to the quantum dynamics of a flat Friedmann-Lemaître- Robertson-Walker model with a massless scalar field in the presence of a small and positive cosmological constant, in the context of Loop Quantum Cosmology. We use a perturbative treatment with respect to the model without a cosmological constant, which is exactly solvable. Our solution is approximate, but it is precisely valid at the high curvature regime where quantum gravity corrections are important. We compute explicitly the evolution of the expectation value of the volume. For semiclassical states characterized by a Gaussian spectral profile, the introduction of a positive cosmological constant displaces the bounce of the solvable model to lower volumes and to higher values of the scalar field. These displacements are state dependent, and in particular, they depend on the peak of the Gaussian profile, which measures the momentum of the scalar field. Moreover, for those semiclassical states, the bounce remains symmetric, as in the vanishing cosmological constant case. However, we show that the behavior of the volume is more intricate for generic states, leading in general to a non-symmetric bounce.

scholarly journals Covariant entropy bound and loop quantum cosmology

2008 ◽  
Vol 78 (6) ◽  
Author(s):  
Abhay Ashtekar ◽  
Edward Wilson-Ewing
Keyword(s):  
Quantum Cosmology ◽  
Loop Quantum Cosmology ◽  
Entropy Bound
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