Séminaire / Seminar GReCO |
| « Signatures of quantum gravity with perfect fluid » |
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Harkirat Singh Sahota |
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The canonical quantization of general relativity is riddled with issues at
the formal level, e.g., observables, the problem of time, choice of ordering, etc. In the context of de-parameterized models (flat-FLRW model with perfect fluid and dust shell collapse in quantum LTB geometry), we aim to address these issues and investigate the signatures of quantum gravity. The standard approach to incorporate the quantum gravity effects into the semiclassical analysis is to adopt a `dressed metric' from the QG model that represents the quantum-corrected regular spacetime. Since the relevant observables are usually made out of conjugate variables that do not commute in QG, the expectation value of only one variable might not suffice. The viability of dressed metric-like approaches is investigated by comparing the expectation value of a general class of ordering of these observables with their dressed counterparts (expressions computed from metric expectation). For the case of dust shell collapse in the quantum LTB model, we study the mode decomposition of a unitarily evolving wave packet. For the observable depicting mode decomposition, we identify incoming and outgoing modes with the eigenstates of operator and estimate their contribution to the radiation profile. The infrared sector of this process demonstrates some characteristic features which turn out to be highly sensitive to the near-bounce dynamics of the dust cloud. |
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vendredi 24 février 2023 - 14:00 Salle des séminaires Évry Schatzman Institut d'Astrophysique de Paris |
| Pages web du séminaire / Seminar's webpage |