MG15 - Talk detail

Back to previous page

 Participant

Institution

Session

Accepted

Order

Time

Talk

Title

Abstract

We propose to deploy limits that arise from different tests of the Pauli Exclusion Principle in order: i) to provide theories of quantum gravity with an experimental guidance; ii) to distinguish among the plethora of possible models the ones that are already ruled out by current data; iii) to direct future attempts to be in accordance with experimental constraints. We firstly review experimental bounds on nuclear processes forbidden by the Pauli Exclusion Principle, which have been derived by several experimental collaborations making use of different detector materials. Distinct features of the experimental devices entail sensitivities on the constraints hitherto achieved that may differ one another by several orders of magnitude. We show that with choices of these limits, renown examples of flat noncommutative space-time instantiations of quantum gravity can be heavily constrained, and eventually ruled out. We devote particular attention to the analysis of the κ-Minkowski and θ-Minkowski noncommutative spacetimes. These are deeply connected to some scenarios in string theory, loop quantum gravity and noncommutative geometry. We emphasize that the severe constraints on these quantum spacetimes, although cannot rule out theories of top-down quantum gravity to whom are connected in various way, provide a powerful limitations of those models that it will make sense to focus on in the future.

Pdf file

Session

Accepted

Order

Time

Talk

Title

Abstract

We discuss possible implications of the recent detection by the LIGO and VIRGO collaboration of the gravitational-wave event GW170817, the signal of which is consistent with predictions in general relativity on the merging of neutron stars. A near-simultaneous and spatially correlated observation of a gamma-ray burst, the GRB 170817A signal, was achieved independently by the Fermi Gamma-ray Burst Monitor, and by the Anti-coincidence Shield for the Spectrometer of the International Gamma-Ray Astrophysics Laboratory. We speculate on the possibility that new dark stars signals could be detected from the LIGO/VIRGO detectors. This proposal, which aims at providing a test for some models of dark matter, relies on the recent achievement of detecting, for visible ordinary matter, the merging of neutron stars both in the gravitational and the electromagnetic channel. A lack of correlation between the two expected signals would suggest a deviation from the properties of ordinary matter. Specifically, we focus on models of invisible dark matter, and in particular we study the case of mirror dark matter, within the framework of which a large amount of mirror neutron stars are naturally envisaged to occupy our dark matter halo. The observation of an electromagnetically hidden event inside the dark matter halo of our galaxy should provide a hint of new physics. There would be indeed no satisfactorily complete explanation accounting for the lack of electromagnetic signal, if only standard neutron star merging were considered to describe events that happen so close to us.

Pdf file

Session

Accepted

Order

Time

Talk

Title

Abstract

We show that the correspondence among $AdS_{3}/CFT_{2}$, the 1D Schwarzian model, SYK model and 3D Loop quantum gravity can be extended to the case of $dS_{3}/CFT_{2}$. The R-matrix, related to the gravitational scattering amplitude near the horizon of $dS_{3}$ black hole, corresponds to a crossing kernel of the holographic in the Schwarzian model side. The R-matrix is related to the 6j-symbol of $SU(1,1)$. We also find that in the Euclidean $dS_{3}$ a new Kac-Moody symmetry of instantons emerges out. We dub these new solutions {\it Kac-Moodions}. A $(1\leftrightarrow 1)$ correspondence of Kac-Moodion levels and $SU(2)$ spin representations is established. In other words, every instanton corresponds to LQG spin representations. The instantons are directly connected to the Black Hole entropy, as punctures on its horizon. This strongly supports the recent proposal, in arXiv:1707.00347, that a Kac-Moody symmetry of gravitational instantons is related to the black hole information processing.

Pdf file

Session

Accepted

Order

Time

Talk

Title

Abstract

The semiclassical effects of anti-evaporating black holes can be discussed in the framework of f(R) gravity. In particular, the Bousso–Hawking–Nojiri–Odinstov anti-evaporation instability of degenerate Schwarzschild–de Sitter black holes (the so-called Nariai spacetime) leads to a dynamical increasing of black hole horizon in f(R) gravity. This phenomenon causes the following transition: emitting marginally trapped surfaces (TS) become space-like surfaces before the effective Bekenstein–Hawking emission time. As a consequence, Bousso–Hawking thermal radiation cannot be emitted in an anti-evaporating Nariai black hole. Possible implications in cosmology and black hole physics are also discussed.

Pdf file

Session

Accepted

Order

Time

Talk

Title

Abstract

We propose to deploy limits that arise from different tests of the Pauli Exclusion Principle in order: i) to provide theories of quantum gravity with an experimental guidance; ii) to distinguish among the plethora of possible models the ones that are already ruled out by current data; iii) to direct future attempts to be in accordance with experimental constraints. We firstly review experimental bounds on nuclear processes forbidden by the Pauli Exclusion Principle, which have been derived by several experimental collaborations making use of different detector materials. Distinct features of the experimental devices entail sensitivities on the constraints hitherto achieved that may differ one another by several orders of magnitude. We show that with choices of these limits, renown examples of flat noncommutative space-time instantiations of quantum gravity can be heavily constrained, and eventually ruled out. We devote particular attention to the analysis of the κ-Minkowski and θ-Minkowski noncommutative spacetimes. These are deeply connected to some scenarios in string theory, loop quantum gravity and noncommutative geometry. We emphasize that the severe constraints on these quantum spacetimes, although cannot rule out theories of top-down quantum gravity to whom are connected in various way, provide a powerful limitations of those models that it will make sense to focus on in the future.

Pdf file

Session

Accepted

Order

Time

Talk

Title

Abstract

Pdf file

Back to previous page