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Report

Teaser, summary, work performed and final results

Periodic Reporting for period 1 - GaugedBH (Black holes in gauged Supergravity: Supersymmetric and Holographic properties)

Teaser

Summary

Although gravity at the classical level is described very well by the theory of general relativity (which is fundamental in the detection of gravitational waves, for example) the very existence of black holes shows inconsistencies with quantum mechanics, in particular with unitarity. The understanding of quantum properties of gravity is one of the biggest unresolved puzzles of modern physics.

The specific objectives for the project are the investigation of black hole evaporation and black hole properties in gauged Supergravity, through a holographic analysis based on the AdS/CFT correspondence. The holographic correspondence is the most developped framework where properties of quantum gravity can be studied.

This research addresses properties of quantum fields near the black hole horizon and conformal quantum field theories in the context of holography, where it is possible to study properties otherwise inaccessible through more conventional, perturbative techniques.

Work performed

Black hole geometries are interpreted as thermal states and one of the main areas of research nowadays is the identification of their microstates.

Since the beginning of the project, I have studied toy models of black holes that could teach aspects of black hole microstates. In one case, I have considered a quantum mechanical toy model, in a perturbative framework; in parallel, I have investigated the time evolutions of wormhole geometries, by studying a double-sided, eternal black hole in anti de Sitter spacetime.

In the first setup it was possible to show how some paradoxes, appearing in the treatment of black hole evaporation, also appear in simple quantum mechanics systems, due to a wrong definition of the perturbative observables. In the setup of eternal black hole, preliminary results show that the semiclassical gravity phase space is not sensitive to the discreteness of the spectrum, as it appears from the CFT side.

Holography has been used also to gather insight on superconformal quantum field theories. First, supersymmetric AdS vacua have been constructed in 7 dimensional gauged supergravity, together with the identification of non-supersymmetric counterparts. Moreover, these vacua, and the possibility of constructing scalar flows between them, perfectly match the conjectured structure of 6d superconformal field theories.

We have contributed to the dissemination of these results through seminars in research institutions around the world, we have organized several scientific events at CERN on quantum gravity and black holes.
Finally, we have participated to a large number of outreach events and gender-awareness initiatives, of which we co-organized an event at CERN.

Final results

\"In order to describe the black hole interior as part of the spacetime, one proposal currently accepted in the literature is to consider \"\"mirror\"\" operators in the dual field theory that cause however a state dependent formulation ofthe problem. State dependence is a feature that is not present in generic quantum field theories. However, this project has explicitly showed that such state dependece can emerge also in the quantum mechanics setup. Moreover, in the context of a toy model it is shown tht many paradoxes that arise in the study of black hole evolution can be linked to the wrong perturbative setup. My investigation has also provided a careful perturbative definition of observables and states, for the toy model considered. These results contribute to define the effective setup where to correctly define black hole unitary evolution in a theory of gravity and quantum fields.

Holography is a very powerful tool that has allowed theoretical physicist not only to learn about quantum gravity from quantum field theories, but also to gather insights on QFT in non-perturbative regime from Supergravity. This project, in particular, has considered 7d gauged supergravity vacua, dual to 6d superconformal field theory (SCFTs). In the literature, 6d SCFTs are constructed as systems of branes and strings from 10 or 11 dimensions. In the large N limit, these systems have a dual gravitational interpretation as Anti de Sitter supersymmetric vacua. This research has constructed new supersymmetric vacua, in one to one correspondence with a class of 6d SCFTs, and has matched the algebraic structure underlying the scalar flows among them to the renormalization group flow conjectured for the 6d SCFTs. This has given evidence in support of the existence and the properties of these theories, based on the AdS/CFT correspondence.\"