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Time uncertainty in quantum gravitational systems

4 pags. | It is generally argued that the combined effect of the Heisenberg principle and general relativity leads to a minimum time uncertainty. Most of the analyses supporting this conclusion are based on a perturbative approach to quantization. We consider a simple family of gravitational models,...

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Quantum time uncertainty in a gravity’s rainbow formalism

9 pags. | The existence of a minimum time uncertainty is usually argued to be a consequence of the combination of quantum mechanics and general relativity. Most of the studies that point to this result are nonetheless based on perturbative quantization approaches, in which the effect of matter on th...

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Particles and vacuum for perturbative and nonperturbative Einstein-Rosen gravity

14 pags. ; appendix. | We discuss the connection between the Fock space introduced by Ashtekar and Pierri for Einstein-Rosen waves and its perturbative counterpart based on the concept of a particle that arises in linearized gravity with a de Donder gauge. We show that the gauge adopted by Ashtekar ...

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Evolution operators for linearly polarized two-Killing cosmological models

13 pags. ; appendix | We give a general procedure to obtain non perturbative evolution operators in closed form for quantized linearly polarized two-Killing vector reductions of general relativity with a cosmological interpretation. We study the representation of these operators in Fock spaces and d...

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Entropy and temperature of black holes in a gravity's rainbow

11 pags. | The linear relation between the entropy and area of a black hole can be derived from the Heisenberg principle, the energy-momentum dispersion relation of special relativity, and general considerations about black holes. There exist results in quantum gravity and related contexts suggestin...

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Conditions for large non-Gaussianity in two-field slow-roll inflation

16 pages, 6 figures, 1 table.-- PACS number: 98.80.Cq. | We study the level of primordial non-Gaussianity in slow-roll two-field inflation. Using an analytic formula for the nonlinear parameter f_NL in the case of a sum or product separable potential, we find that it is possible to generate signific...