-
Clare Burrage30/06/2026, 13:05
If light scalars that couple to matter are present in the early universe, then when matter particles become non-relativistic this 'kicks' the scalar field and can cause rapid scalar evolution. I will discuss the implications of this for the misalignment production of ultra-light scalar dark matter, as well as for dynamical dark energy models.
Go to contribution page -
Graham White (Southampton)30/06/2026, 13:55
Electroweak baryogenesis is one of the major paradigms for explaining why there is more matter than anti matter. The production of a chiral asymmetry from interactions with the bubble wall remains crudely understood as different methods produce wildly different outcomes. We derive a set of Boltzmann equations using three different methods in the case of a neutralino extension to the Standard...
Go to contribution page -
Claire Rigouzzo (King's College London)30/06/2026, 14:45
Precise polarization measurements of the Cosmic Microwave Background (CMB) provide an opportunity to rigorously test the standard cosmological model. The correlation between E and B
Go to contribution page
modes, indicative of cosmic birefringence, is expected to arise from parity-violating physics in the
Universe. However, detecting these EB correlations remains extremely challenging as it demands
exceptionally... -
Hyungjin Kim (IPhT)30/06/2026, 16:00
I will discuss gravitational probes of ultralight dark matter. Using astrophysical density fluctuations, I will show that experimental and observational setup designed for gravity wave detection can be used for dark matter search as well. This include interferometers, pulsar timing, astrometry, and solar system dynamics. I will discuss the reach of each setup and future prospects.
Go to contribution page -
Angus Spalding (Univeristy of Southampton)30/06/2026, 16:50
I will show that spectral features of a gravitational-wave background can directly determine the Lagrangian parameters of BSM particles, independently of the gravitational-wave production mechanism. Long-lived particles generically induce a temporary period of early matter domination in the thermal history of the Universe, imprinting two characteristic frequencies in any primordial...
Go to contribution page -
Duarte Feiteira30/06/2026, 17:25
In this talk, I will discuss the gravitational production of scalars and fermions during inflation. For scalars, I will compare Bogolyubov coefficient and Starobinsky stochastic approaches, showing that they only agree in the limit of infinitely long inflation. High-scale inflation is very efficient in particle production, leading to constraints on the existence of free, light, and stable...
Go to contribution page -
Eemeli Tomberg (UCLouvain)01/07/2026, 09:00
Stochastic inflation is a method for computing super-Hubble perturbations beyond the small-perturbation limit. I show how to obtain the radial profile of the curvature perturbations in a random patch of space using this method. The profiles turn out to be spiky, far from the smooth mean profiles often considered in the literature. Based on extensive numerical simulations, I discuss the...
Go to contribution page -
Chiara Animali01/07/2026, 09:40
Stochastic inflation can be implemented on stochastic trees, modelling the inflationary expansion as a branching process. Stochastic trees do not operate on a fixed background, instead new spacetime units dynamically emerge as the trees unfold, naturally incorporating metric fluctuations. The tree structure naturally encodes the statistics of curvature perturbations and other cosmological...
Go to contribution page -
Baptiste Blachier01/07/2026, 10:50
Cosmic inflation may exhibit stochastic periods during which quantum fluctuations dominate over the semi-classical evolution. Extracting observables in these regimes is a notoriously difficult program as quantum randomness makes them fully probabilistic.
We propose a new way of framing Stochastic Inflation by enforcing the point of view of a local observer for which inflation has ended i.e....
Go to contribution page -
Parth Bhargava (Institute of Cosmology and Gravitation (ICG), Portsmouth)01/07/2026, 11:25
Quantum fluctuations during cosmic inflation inevitably generate inhomogeneities and anisotropies on all observable scales and beyond. The $\delta N$ formalism provides a powerful framework to describe the nonlinear curvature perturbation in terms of fluctuations in the duration of inflation, $N$. In its standard implementation, $\delta N$ is calculated using the classical trajectory to find...
Go to contribution page -
Prof. Subir Sarkar (University of Oxford)01/07/2026, 13:30
When Peccei-Quinn symmetry breaks after inflation, domain walls will form in the axion field at the QCD crossover if there is more than one quark charged under the symmetry. Destabilised by quantum gravity effects, the collapse of the wall network creates relativistic axions, which subsequently turn non-relativistic and become dark matter. Accounting for this additional contribution requires...
Go to contribution page -
FRANCESCA,VALERY CHADHA-DAY01/07/2026, 14:15
Light axion-light particles (ALPs) can act as dark matter, dark energy or dark radiation depending on their mass and production mechanism. Determining the spectrum of ALP masses and couplings is therefore crucial for cosmology. I will give an overview of experimental and observational ALP searches and how these can be combined to measure the axiverse spectrum.
Go to contribution page -
Tom Melia01/07/2026, 15:30
Real-time quantum simulations of gauge theories on controllable quantum platforms require a careful treatment of gauge constraints, and a variety of approaches have been developed to implement them. I will discuss these ideas and explore analogous questions for canonical gravity and cosmology, arguing that the way constraints are treated in quantum simulations may itself teach us something...
Go to contribution page -
Alex Jenkins (University of Cambridge)01/07/2026, 16:15
False vacuum decay plays a pivotal role in the physics of the early Universe. However, we lack a satisfying theoretical understanding of this process, with existing approaches working only in imaginary time, and relying on untested assumptions and approximations. In this talk, I will describe ongoing efforts to simulate vacuum decay in tabletop experiments, using ultra-cold atomic condensates...
Go to contribution page -
Emilie Hertig (University of Cambridge)01/07/2026, 17:00
False vacuum decay (FVD) plays a central role in early-Universe cosmology, with implications for inflationary dynamics, baryogenesis, and Higgs stability. While this type of first-order phase transition is traditionally described using Euclidean instanton methods, the recent development of semiclassical lattice simulations has enabled us to model the decay process in real time.
Go to contribution page
In this talk,... -
Juan Urrutia (KBFI)02/07/2026, 09:00
We explore the statistical properties of stochastic diffractive lensing, in which the amplitudes and phases of a phase-coherent gravitational wave signal fluctuate due to the collective wave-optics imprint of many light Dark Matter halos. For LISA, the effect is primarily driven by halos of $\mathcal{O}\left(10-10^4\,M_{\odot}\right)$ and rises above the noise for loud massive black-hole...
Go to contribution page -
James Alvey (University of Cambridge)02/07/2026, 09:40
Gravitational-wave astronomy began with LIGO's first detection in 2015. Since then, the LIGO–Virgo–KAGRA network has reported on hundreds of compact-binary mergers - reshaping our view of the Universe, from neutron-star nucleosynthesis to precision cosmology and tests of gravity. Recently, pulsar timing arrays have also opened up the nanohertz window with strong evidence for a low-frequency...
Go to contribution page -
Prof. Arttu Rajantie (Imperial College London)02/07/2026, 10:55
The effective potential is a powerful and widely used tool in quantum field theory. However, in de Sitter spacetime, which is a good approximation for the inflationary era, it lacks a unique definition. In this talk, I discuss the constraint effective potential, which is equivalent to the usual textbook definition in Minkowski spacetime but differs significantly for light fields in de Sitter....
Go to contribution page -
DHRUV PASARI (Durham University)02/07/2026, 11:40
Domain walls beyond the textbook Z₂ kink have been studied analytically and through effective models, but seldom simulated directly on the lattice. We close that gap, evolving Z₃ and Z₄ wall networks with CosmoLattice. These networks are qualitatively richer than Z₂: walls come in distinct species, meet along junctions, and can transmute into one another rather than simply annihilating. To...
Go to contribution page -
Djuna Croon02/07/2026, 12:15
-
Tom Melia
Real-time quantum simulations of gauge theories on controllable quantum platforms require a careful treatment of gauge constraints, and a variety of approaches have been developed to implement them. I will discuss these ideas and explore analogous questions for canonical gravity and cosmology, arguing that the way constraints are treated in quantum simulations may itself teach us something...
Go to contribution page -
Arttu Rajantie
-
James Alvey (University of Cambridge)
Choose timezone
Your profile timezone: