Talk detail

Participant	Brighenti, Francesco
Institution	Università di Urbino - Via Santa Chiara - Urbino - Marche - Italy

Session	QG2	Accepted		Order	Time
Talk	Oral abstract	Title	Thermal Dimension Of Quantum Spacetime: Comparison With The Spectral Dimension And Application In Cosmology
Coauthors
Abstract	Recent results suggest that a crucial crossroad for quantum gravity is the characterization of the effective dimension of spacetime at short distances, where quantum properties of spacetime become significant. This is relevant in particular for various scenarios of "dynamical dimensional reduction" which have been discussed in the literature. We are here concerned with the fact that the related research effort has been based mostly on analyses of the "spectral dimension", which involves an unphysical Euclideanization of spacetime and is highly sensitive to the off-shell properties of a theory. As here shown, different formulations of the same physical theory can have wildly different spectral dimension. We propose that dynamical dimensional reduction should be described in terms of the "thermal dimension" which we here introduce, a notion that only depends on the physical content of the theory. We analyze a few models with dynamical reduction both of the spectral dimension and of our thermal dimension, finding in particular some cases where thermal and spectral dimension agree, but also some cases where the spectral dimension has puzzling properties while the thermal dimension gives a different and meaningful picture. We also apply this formalism to the study of thermal and vacuum perturbations in a toy model of the early universe.
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Session	GW9	Accepted		Order	Time
Talk	Poster abstract	Title	Ranking The Galaxies Within A Gravitational-Wave Sky Localization
Coauthors
Abstract	The recent detection of a binary neutron star merger by the LIGO and Virgo collaborations and its corresponding electromagnetic counterpart from several astronomer teams marks the birth of gravitational astronomy. Due to the size of the error regions, which can span tens to thousands of square degrees, there are significant benefits to rank the galaxies inside these large sky areas to maximize the probability of counterpart detection. Here we present a new procedure to query the galaxy catalogs, rank the galaxies and eventually define a prior for time allocation and scheduling algorithms.
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