New Developments in Theoretical Cosmology

Contribution List

4. Holography in the static patch

Damian Galante (KCL)

12/02/2025, 10:00

Morning session 1

In this talk I will review recent progress towards formulating a holographic theory for the de Sitter static patch, from the point of view of an inertial observer. One of the main obstructions to achieve this is the lack of an asymptotic timelike boundary. I will discuss two ways of, at least partially, overcoming this issue. One way is to consider gravity in the presence of a finite boundary....

9. Cosmological Correlators Through the Looking Glass

David Stefanyszyn (University of Nottingham)

12/02/2025, 11:15

Morning session 1

I will discuss parity violation in the early universe. I’ll outline a no-go theorem that states that vanilla inflation cannot produce parity-violating inflationary correlators, then show how including additional massive states in the early universe can yield non-zero signals that take an intriguing factorised form. For example, the parity odd four-point function of scalar perturbations can be...

5. From Strings to Stars: Unlocking the Universe's Acceleration

Ivonne Zavala (University of Swansea)

12/02/2025, 13:00

Afternoon session 1

Recent cosmological observations suggest that dark energy, the driver of the universe's accelerated expansion, may be evolving over time. This challenges the conventional idea of a static cosmological constant within the standard model of cosmology. In this talk, I will explore recent theoretical developments in understanding the nature of dark energy from the perspective of string theory....

8. An Open Effective Field Theory for light in a medium

Thomas Colas (University of Cambridge)

12/02/2025, 13:45

Afternoon session 1

Open effective field theories seek to incorporate dissipation and noise into our theoretical toolbox. These effects arise from the incomplete modelling of unknown components, which can significantly alter the dynamics of observable degrees of freedom. In this talk, I will introduce open electromagnetism, a sandbox for exploring gauge symmetries in open systems, which describes light in...

10. From Holographic Correlators in the Sky to Euclidean AdS

Charlotte Sleight (University of Naples)

12/02/2025, 14:15

Afternoon session 1

1. Cosmological Dressing Rules

Arthur Lipstein (University of Durham)

12/02/2025, 15:30

Afternoon session 2

The basic observables in cosmology are known as in-in correlators. Recent calculations have revealed that in-in correlators in de Sitter space exhibit hidden simplicity stemming from a close relation to scattering amplitudes in flat space. In this talk, I will explain how to make this property manifest by dressing flat space Feynman diagrams with certain auxiliary propagators. Such dressing...

6. Exact results for de Sitter QFTs

Alan Rios Fukelman (KCL)

12/02/2025, 16:15

Afternoon session 2

In this talk I will discuss some recent developments in the study of quantum fields on a fixed de Sitter background. I will discuss the two-dimensional Schwinger model of a massless charged fermion coupled to an Abelian gauge field. The theory admits an exact solution that can be analyzed efficiently using Euclidean methods. I will discuss the fully non-perturbative, all loop correlation...

7. Lessons from the self-dual sector

Silvia Nagy (University of Durham)

12/02/2025, 16:45

Afternoon session 2

In this talk, I will explore how the self-dual sector of gravity and Yang-Mills theory provides a natural framework for formulating an elegant version of the double copy in curved spacetimes. Additionally, I will discuss how this perspective sheds light on the soft limits of these theories, offering a deeper understanding of their asymptotic behaviour.