Events Archive 2025

Energy conditions are attempts to summarise the properties of realistic descriptions of matter, encapsulating for example the idea that energy densities should be positive. Being such general statements, they can have very profound consequences, for example ruling out wormholes and superluminal travel. However, the classical energy conditions are all violated ...

The conformal bootstrap is a framework which aims to classify conformal field theories in diverse dimensions via symmetry and consistency arguments. In this talk, I will provide an introduction to the key ideas underlying this approach. Following this, the discussion will focus on the new structures and complications that arise ...

Active constituents burn fuel to sustain individual motion, giving rise to collective effects that are not seen in systems at thermal equilibrium, such as phase separation with purely repulsive interactions. There is a great potential in harnessing the striking phenomenology of active matter to build novel controllable and responsive materials ...

The singularity theorems developed by Roger Penrose and Stephen Hawking are profound and fundamental results in General Relativity. They proved that spacetime singularities would form under general physical conditions relevant to gravitational collapse and expanding universes, without the assumption of high degrees of symmetry that had been present in previous ...

In this talk I provide some of the key mathematical ingredients of the effective field theory formalism which is used to describe diffractive cross sections. This is intended as a deeper dive into the theoretical setup that leads to the final result presented in my colloquium. In particular I discuss ...

The Lie group SL(2,C) is the simply-connected cover of the Lorentz group. Understanding its representation theory is therefore vital to understanding Lorentz-invariant theories. The standard irreps that one encounters in QFT are indexed by two half integers, which correspond to left and right chirality. These irreps have one ...

Theoretical research on gravitational waveforms from compact binary inspirals (of the kind observed for example at LIGO) has been reinvigorated in recent years by an influx of ideas and techniques from collider physics, especially techniques used to understand the Standard Model at the Large Hadron Collider. I will explain the ...

Einstein's equations imply that a gravitationally collapsed object forms an event horizon. But what lies on the other side of this horizon? In this talk, we question the reality of the conventional solution (the black hole), and point out another, topologically distinct solution: the black mirror. In the black ...

Despite its age and numerous successes, the principle of holography is often misconstrued either as a mere offshoot of string theory or as being based on a series of mysterious identifications of black hole physics with thermodynamics. In particular, any intuition one could hope to gain from these perspectives is ...

This talk provides insight into how topological solitons emerge within the framework of nuclear physics. The lack of understanding how the properties of baryons and nuclei arise from first principles in Quantum Chromodynamics (QCD) has led to the development of various Effective Field Theories (EFTs). Among these, the Skyrme theory ...

In this seminar, I will give an introduction to catastrophe theory and derive Thom’s “seven elementary catastrophes” in the physicist’s (rather than mathematician’s) language. Starting from critical points and structural stability, I will derive the characteristic geometries of the caustics and discuss how they arise in various ...

We revisit the cosmological perturbations in minimal single-field inflation, focusing on subtleties arising from total time derivatives (boundary terms) in their action and the corresponding slow-roll unsuppressed phase in the wave functional. While these total derivatives do not contribute to field correlators, they can significantly influence processes related to momentum-space ...

In this talk I seek to present the mystery of vanishing Love in a Black Hole. It is well-known that Black Holes exhibit no Tidal response - characterised by their 'Love Numbers' - however to date there remains no completely satisfying explanation as to why. This talk will largely be pedagogical, focusing ...

Abstract: We discuss the structure of 2-> N scattering in QCD and gravity in high energy Regge asymptotics and outline remarkable similarities between the two. In the QCD case, the rapid growth of the N-gluon amplitude, described by the BFKL equation, leads to the emergence of nonperturbative classical lumps that ...

Given a gauge Lie algebra, it is natural to seek representations for four-dimensional spacetime fermions that are anomaly-free and chiral. Even for irreducible representations, where the problem reduces to studying su(n) for n≥3, solutions seem to be few and far between: a trial-and-error scan by Eichten, Kang and ...