Matterdriven phase transition in lattice quantum gravity
The model of Causal Dynamical Triangulations (CDT) is a backgroundindependent and diffeomorphisminvariant approach to quantum gravity,
Getting hot without accelerating: vacuum thermal effects from conformal quantum mechanics
In this talk I will discuss how the generators of radial conformal symmetries in Minkowski spacetime are related to the generators of time evolution in conformal quantum mechanics. Within this correspondence I will show that in conformal quantum mechanics the state corresponding to the inertial vacuum for a conformally invariant field in Minkowski spacetime has the structure of a thermofield double. The latter is built from a bipartite "vacuum state" corresponding to the ground state of the generators of hyperbolic time evolution, which cover only a portion of the time domain.
Underground tests of Quantum Mechanics: Gravityrelated and CSL wave function collapse models
We are experimentally investigating possible departures from the standard quantum mechanics’ predictions at the Gran Sasso underground laboratory in Italy. In particular, with radiation detectors we are searching signals predicted by the collapse models (spontaneous emission of radiation) which were proposed to solve the “measurement problem” in quantum physics and signals coming from a possible violation of the Pauli Exclusion Principle.
Debate on Asymptotically Safe Quantum Gravity

John Donoghue University of Massachusetts Amherst

Roberto Percacci SISSA Scuola Internazionale Superiore di Studi Avanzati
Asymptotically safe gravity is one of the most conservative approaches to quantum gravity. It relies on the framework of quantum field theory and the Wilsonian renormalization group. Recently, questions and open issues have been discussed both within and outside its community.
Interplay of quantum gravity and matter: Role of symmetries
Across different scales, symmetries shape physical systems: for example, in effective theories in condensed matter, various global symmetries are realized; at higher energy scales, the local symmetries of the Standard Model of particle physics take over. But what is the fate of symmetries at the Planck scale, where quantum gravity fluctuations kick in?
A Generalized HartleHawking State
The HartleHawkingVilenkin state is defined on minisuperspace and is semiclassically related to inflationary theory. However, the state suffers a few problems connected to the path integral of Euclidean or the Lorentzian measure of metrics. In this talk, we will explore a way around these issues by working in the (Ashtekar) connection representation, a real KodamaChernSimons state. We find a generalized "Fourier Transform" that related the ChernSimonsKodama state to the HartleHawking state beyond minisuperspace. We end with some discussion and open ended questions for cosmology
Null infinity from quasilocal phase space
I will consider the phase space at nullinfinity from the r\rightarrow\infty limit of a quasilocal phase space for a finite box with a boundary that is null. This box will serve as a natural IR regulator. To remove the IR regulator, I will consider a double null foliation together with an adapted NewmanPenrose null tetrad. The limit to null infinity (on phase space) is obtained in the limit where the boundary is sent to infinity. I will introduce various charges and explain the role of the corresponding balance laws. The talk is based on the paper: arXiv:2012.01889.
Deformations of General Relativity, Geometrodynamics and reality conditions
A remarkable aspect of 4dimensional complexified General Relativity (GR) is that it can be nontrivially deformed: there exists an infiniteparameter set of modifications with the same degree of freedom count. It is trivial to impose reality conditions that lead to real theories with Euclidean or split signature, but the situation is more complicated and not yet fully understood in the Lorentzian case, which is the subject of this talk.
Galilean and Carrollian relativities in noncommutative spacetime models
I describe the nonrelativistic c→∞ and ultrarelativistic c→0 limits of the kappadeformed symmetries, with and without a cosmological constant. The corresponding kappaNewtonian and kappaCarrollian noncommutative spacetimes are also obtained. These constructions show the nontrivial interplay between the quantum deformation parameter kappa, the curvature parameter Lambda and the speed of light parameter c.
What happens at the end of Hawking's evaporation?
There are three distinct regions where quantum gravity becomes nonnegligible in a black hole spacetime. There is a precise sense in which these three regions are causally disconnected, and therefore arguably independent. I illustrate a number of indications we have about what happens in each of them, coming both from the classical Einstein equations and from loop quantum gravity. These point all to an interesting scenario: long living remnants stabilized by quantum gravity, formed by a large and slowly decreasing interior enclosed into a small antitrapping horizon.