Triangle Seminars
Tuesday, 27 Oct 2020
Moduli stars
Francesco Muia
(Theory Group DESY)
Abstract:
The recent direct detection of gravitational waves (GWs) has opened a new window of observation for physical phenomena in which gravity is the dominant interaction. Collisions of black holes and neutron stars have been observed and a plethora of new events, even involving new physics, are expected to be detected in the next few years. It is natural to explore alternative physical objects that may exist which are different from the standard stars and black holes and that could lead to particular imprints on the GW spectrum. In this talk I will explore the possibility that moduli (gravitationally coupled scalar fields arising in all string compactifications) can compose star-like objects (moduli stars) whose dynamics gives rise to GW production. I will illustrate their formation in the early universe, that has been studied through lattice techniques. After their formation moduli stars can have different behaviours, e.g. they could rapidly collapse to black holes or disperse into scalar radiation, resulting in different phenomenology. I will describe the fate of moduli stars, that has been investigated through numerical relativity techniques.
[please email a.held@imperial.ac.uk for zoom link or password]
The recent direct detection of gravitational waves (GWs) has opened a new window of observation for physical phenomena in which gravity is the dominant interaction. Collisions of black holes and neutron stars have been observed and a plethora of new events, even involving new physics, are expected to be detected in the next few years. It is natural to explore alternative physical objects that may exist which are different from the standard stars and black holes and that could lead to particular imprints on the GW spectrum. In this talk I will explore the possibility that moduli (gravitationally coupled scalar fields arising in all string compactifications) can compose star-like objects (moduli stars) whose dynamics gives rise to GW production. I will illustrate their formation in the early universe, that has been studied through lattice techniques. After their formation moduli stars can have different behaviours, e.g. they could rapidly collapse to black holes or disperse into scalar radiation, resulting in different phenomenology. I will describe the fate of moduli stars, that has been investigated through numerical relativity techniques.
[please email a.held@imperial.ac.uk for zoom link or password]
Posted by: IC
Wednesday, 28 Oct 2020
Non-perturbative physics for JT gravity and supergravity
Clifford Johnson
(USC)
Abstract:
Jackiw–Teitelboim (JT) gravity and supergravity theories are exciting solvable models that teach us about low temperature black hole dynamics, and aspects of quantum chaotic behaviour. They have been shown (by Saad, Shenker and Stanford, and by Stanford and Witten) to have double scaled random matrix model descriptions, capturing the (spacetime) topological perturbative expansion of the partition function. I will describe an alternative method for building the matrix model description, using techniques from minimal string theory. This method is particularly useful for supplying non-perturbative definitions of the physics. I show how this allows for the computation of key aspects of the physics at low energy and temperature.
For the zoom link, please email antoine.brgt@gmail.com
Jackiw–Teitelboim (JT) gravity and supergravity theories are exciting solvable models that teach us about low temperature black hole dynamics, and aspects of quantum chaotic behaviour. They have been shown (by Saad, Shenker and Stanford, and by Stanford and Witten) to have double scaled random matrix model descriptions, capturing the (spacetime) topological perturbative expansion of the partition function. I will describe an alternative method for building the matrix model description, using techniques from minimal string theory. This method is particularly useful for supplying non-perturbative definitions of the physics. I show how this allows for the computation of key aspects of the physics at low energy and temperature.
For the zoom link, please email antoine.brgt@gmail.com
Posted by: IC
Thursday, 29 Oct 2020
From Quantum Field Theory to Quantum Gravity and the Sachdev-Ye-Kitaev model
Adrian Tanasa
(Univ. Bordeaux)
Abstract:
Zoom link: Please email Silvia Nagy (s.nagyATqmul.ac.uk) or Jungwook Kim (jung-wook.kimATqmul.ac.uk) for the zoom link
Abstract: In the first part of this talk I will briefly introduce 0-dimensional Quantum Field Theory (QFT) and Matrix Models, which are known to be a succesfull discrete geometrical, QFT approach to 2D Quantum Gravity. I will then move on to Tensor Models, seen as natural QFT generalization of the celebrated Matrix Models. In the next part of the talk I will present the Sachdev-Ye-Kitaev model, which is known to be a toy model for holography, as well as the relations of this SYK model with various Tensor Models. Finally, I will present some recent results on these topics (various diagrammatic results but also the study of the effect of non-Gaussian average over the SYK random couplings).
Zoom link: Please email Silvia Nagy (s.nagyATqmul.ac.uk) or Jungwook Kim (jung-wook.kimATqmul.ac.uk) for the zoom link
Abstract: In the first part of this talk I will briefly introduce 0-dimensional Quantum Field Theory (QFT) and Matrix Models, which are known to be a succesfull discrete geometrical, QFT approach to 2D Quantum Gravity. I will then move on to Tensor Models, seen as natural QFT generalization of the celebrated Matrix Models. In the next part of the talk I will present the Sachdev-Ye-Kitaev model, which is known to be a toy model for holography, as well as the relations of this SYK model with various Tensor Models. Finally, I will present some recent results on these topics (various diagrammatic results but also the study of the effect of non-Gaussian average over the SYK random couplings).
Posted by: QMW
The TTbar deformation and a promising 4D generalisation
Roberto Tateo
(University of Torino)
Abstract:
Two-dimensional field theories deformed by Zamolodchikov's TTbar operator have recently attracted the attention of theoretical physicists due to the many important links with string theory and AdS/CFT.
In this talk, I will describe various classical and quantum aspects of this particular irrelevant perturbation, including its geometrical interpretation at the classical level.
I will also introduce a generalisation of this geometrical framework to 4D field theories, and discuss some of the interesting differences with the 2D case. –– Part of London Integrability Journal Club. If you are a new participant, please register filling the form at integrability-london.weebly.com. The link will be emailed.
Two-dimensional field theories deformed by Zamolodchikov's TTbar operator have recently attracted the attention of theoretical physicists due to the many important links with string theory and AdS/CFT.
In this talk, I will describe various classical and quantum aspects of this particular irrelevant perturbation, including its geometrical interpretation at the classical level.
I will also introduce a generalisation of this geometrical framework to 4D field theories, and discuss some of the interesting differences with the 2D case. –– Part of London Integrability Journal Club. If you are a new participant, please register filling the form at integrability-london.weebly.com. The link will be emailed.
Posted by: andrea