Found at least 20 result(s)
Regular Seminar Sunil Mukhi (IISER, Pune)
at: 10:30 room LIMS abstract: | These lectures will summarise mathematical aspects of classical General Relativity that are helpful in understanding current developments in the field. Lecture I will focus on Lorentzian-signature geometry, with an emphasis on causal structure. Some topological notions will also be introduced. In Lecture II we will go on to study the behaviour of geodesics in General Relativity and derive the famous Raychaudhuri equation. The null version of this equation, due to Sachs, will also be derived. Lecture III will focus on the "Hawking singularity theorem", namely that cosmological spacetimes with positive local Hubble constant are geodesically incomplete in the past under suitable conditions. In Lecture IV we will discuss the "Penrose singularity theorem" for black holes. |
Regular Seminar Sunil Mukhi (IISER, Pune)
at: 10:30 room LIMS abstract: | These lectures will summarise mathematical aspects of classical General Relativity that are helpful in understanding current developments in the field. Lecture I will focus on Lorentzian-signature geometry, with an emphasis on causal structure. Some topological notions will also be introduced. In Lecture II we will go on to study the behaviour of geodesics in General Relativity and derive the famous Raychaudhuri equation. The null version of this equation, due to Sachs, will also be derived. Lecture III will focus on the "Hawking singularity theorem", namely that cosmological spacetimes with positive local Hubble constant are geodesically incomplete in the past under suitable conditions. In Lecture IV we will discuss the "Penrose singularity theorem" for black holes. |
Regular Seminar Sunil Mukhi (ICTS)
at: 10:30 room LIMS abstract: | These lectures will summarise mathematical aspects of classical General Relativity that are helpful in understanding current developments in the field. Lecture I will focus on Lorentzian-signature geometry, with an emphasis on causal structure. Some topological notions will also be introduced. In Lecture II we will go on to study the behaviour of geodesics in General Relativity and derive the famous Raychaudhuri equation. The null version of this equation, due to Sachs, will also be derived. Lecture III will focus on the "Hawking singularity theorem", namely that cosmological spacetimes with positive local Hubble constant are geodesically incomplete in the past under suitable conditions. In Lecture IV we will discuss the "Penrose singularity theorem" for black holes. |
Regular Seminar Sunil Mukhi (ICTS)
at: 13:30 room LIMS abstract: | These lectures will summarise mathematical aspects of classical General Relativity that are helpful in understanding current developments in the field. Lecture I will focus on Lorentzian-signature geometry, with an emphasis on causal structure. Some topological notions will also be introduced. In Lecture II we will go on to study the behaviour of geodesics in General Relativity and derive the famous Raychaudhuri equation. The null version of this equation, due to Sachs, will also be derived. Lecture III will focus on the "Hawking singularity theorem", namely that cosmological spacetimes with positive local Hubble constant are geodesically incomplete in the past under suitable conditions. In Lecture IV we will discuss the "Penrose singularity theorem" for black holes. |
Informal Seminar Herman Verlinde (Princeton)
at: 10:00 room LIMS, Royal Institution abstract: | an informal in-person seminar by Prof. Herman Verlinde |
Regular Seminar Claudia de Rham (Imperial College)
at: 10:30 room LIMS abstract: | CANCELLED due to an unforeseen speaker emergency. |
Regular Seminar Claudia de Rham (Imperial College)
at: 10:30 room LIMS abstract: | CANCELLED due to an unforeseen speaker emergency. |
Regular Seminar Claudia de Rham (Imperial College)
at: 10:30 room LIMS abstract: | CANCELLED due to an unforeseen speaker emergency. |
Regular Seminar Claudia de Rham (Imperial College)
at: 10:30 room LIMS abstract: | CANCELLED due to an unforeseen speaker emergency. |
Regular Seminar Matthew Dodelson (CERN)
at: 16:00 room LIMS abstract: | This is part of HoloUK2. Registration is free but space is limited, so please register at https://sites.google.com/view/holouk/home/holouk-2. Correlators in field theories at finite temperatures have singularities on the light cone. Are there any other singularities? In this talk, I will address this question in the context of holographic theories in the black hole phase. Two points on the AdS boundary can be connected by a null geodesic in the bulk, leading to a so-called bulk-cone singularity. These new singularities were previously conjectured by analyzing the geodesic approximation, but we will derive them in full generality by developing the technology of thermal Regge theory. The functional form of the singularity leads to sharp signatures of the AdS photon sphere in the boundary CFT, including an identification of the boundary dual of the angular velocity and Lyapunov exponent associated with the photon sphere. I will also comment on the resolution of the singularity by stringy effects. |
Regular Seminar Gabriel Wong (Oxford)
at: 14:00 room LIMS abstract: | This is part of HoloUK2. Registration is free but space is limited, so please register at https://sites.google.com/view/holouk/home/holouk-2. One of the major insights gained from holographic duality is the relation between the physics of black holes and quantum chaotic systems. This relation is made precise in the duality between two dimensional JT gravity and random matrix theory. In this work, we generalize this to a duality between AdS3 gravity and a random ensemble of approximate CFT's. The latter is described by a combined tensor and matrix model, describing the OPE coefficients and spectrum of a theory that approximately satisfies the bootstrap constraints. We show that the Feynman diagrams of the random ensemble produce a sum over 3 manifolds that agrees with the partition function of 3d gravity. A crucial element of this dictionary is the Virasoro TQFT, which defines the bulk gravitational path integral via the cutting and sewing relations of topological field theory. This TQFT has gravitational edge modes degrees of freedom whose entanglement gives rise to gravitational entropy. |
Regular Seminar Petr Kravchuk (King's)
at: 10:30 room LIMS abstract: | In these lectures we will discuss various aspects of conformal field theories in Lorentzian signature. First, we will study the general properties of Lorentzian correlation functions, including their global conformal structure and the relation to Euclidean correlators. We will then consider the Regge limit of correlation functions and how this limit requires the introduction of complex spin. We will define complex spin using the Lorentzian inversion formula, and interpret it in terms of non-local light-ray operators. Finally, we will discuss applications of light-ray operators to even shape observables. |
Regular Seminar Petr Kravchuk (King's)
at: 10:30 room LIMS abstract: | In these lectures we will discuss various aspects of conformal field theories in Lorentzian signature. First, we will study the general properties of Lorentzian correlation functions, including their global conformal structure and the relation to Euclidean correlators. We will then consider the Regge limit of correlation functions and how this limit requires the introduction of complex spin. We will define complex spin using the Lorentzian inversion formula, and interpret it in terms of non-local light-ray operators. Finally, we will discuss applications of light-ray operators to even shape observables. |
Colloquium Peter Cameron (St Andrews and Queen Mary)
at: 18:00 room LIMS, Royal Institution abstract: | In the inaugural Simon Norton Lecture, Prof. Peter Cameron will celebrate the mathematician's achievements and talk about Norton algebras. https://lims.ac.uk/event/a-monstrous-talent/ |
Regular Seminar Petr Kravchuk (King's)
at: 10:30 room LIMS abstract: | In these lectures we will discuss various aspects of conformal field theories in Lorentzian signature. First, we will study the general properties of Lorentzian correlation functions, including their global conformal structure and the relation to Euclidean correlators. We will then consider the Regge limit of correlation functions and how this limit requires the introduction of complex spin. We will define complex spin using the Lorentzian inversion formula, and interpret it in terms of non-local light-ray operators. Finally, we will discuss applications of light-ray operators to even shape observables. |
Regular Seminar Petr Kravchuk (King's)
at: 10:30 room LIMS abstract: | In these lectures we will discuss various aspects of conformal field theories in Lorentzian signature. First, we will study the general properties of Lorentzian correlation functions, including their global conformal structure and the relation to Euclidean correlators. We will then consider the Regge limit of correlation functions and how this limit requires the introduction of complex spin. We will define complex spin using the Lorentzian inversion formula, and interpret it in terms of non-local light-ray operators. Finally, we will discuss applications of light-ray operators to even shape observables. |
Regular Seminar Pau Figueras (QMUL)
at: 14:00 room LIMS abstract: | In these series of lectures we will explore initial value problem in general relativity and how it can be solved in a computer in practical situations. We will first cover the necessary mathematical foundations, including the concepts of well-posedness and strong hyperbolicity, and then explore the current formulations of Einstein’s theory of gravity that are implemented in modern numerical codes, namely generalised harmonic coordinates and the BSSN formulation. We shall see how the latter can be implemented in a toy code so as to get some hands on experience. Time permitting, we will also explore the initial boundary value problem in asymptotically anti-de Sitter spaces and how it can be solved in practice using the characteristic formulation of the Einstein equations in applications of holography. |
Regular Seminar Pau Figueras (QMUL)
at: 10:30 room LIMS abstract: | In these series of lectures we will explore initial value problem in general relativity and how it can be solved in a computer in practical situations. We will first cover the necessary mathematical foundations, including the concepts of well-posedness and strong hyperbolicity, and then explore the current formulations of Einstein’s theory of gravity that are implemented in modern numerical codes, namely generalised harmonic coordinates and the BSSN formulation. We shall see how the latter can be implemented in a toy code so as to get some hands on experience. Time permitting, we will also explore the initial boundary value problem in asymptotically anti-de Sitter spaces and how it can be solved in practice using the characteristic formulation of the Einstein equations in applications of holography. |
Regular Seminar Organizers Toby Wiseman - Pau Figueras (LIMS)
at: 12:00 room LIMS, Royal Institution abstract: | A day for gravity |
Regular Seminar Pau Figueras (QMUL)
at: 10:30 room LIMS abstract: | In these series of lectures we will explore initial value problem in general relativity and how it can be solved in a computer in practical situations. We will first cover the necessary mathematical foundations, including the concepts of well-posedness and strong hyperbolicity, and then explore the current formulations of Einstein’s theory of gravity that are implemented in modern numerical codes, namely generalised harmonic coordinates and the BSSN formulation. We shall see how the latter can be implemented in a toy code so as to get some hands on experience. Time permitting, we will also explore the initial boundary value problem in asymptotically anti-de Sitter spaces and how it can be solved in practice using the characteristic formulation of the Einstein equations in applications of holography. |