Monday, April 29 |
07:30 - 09:00 |
Breakfast (Restaurant at your assigned hotel) |
09:15 - 09:30 |
Introduction and Welcome (Conference Room San Felipe) |
09:30 - 10:30 |
Gianmassimo Tasinato: Probing the Physics of the Early Universe with Gravitational Interferometers ↓ Cosmological inflation predicts the existence of a stochastic background of gravitational waves, whose features depend on the model of inflation under consideration. There exist well motivated frameworks predicting an enhancement of the primordial gravity wave spectrum at frequency scales testable with gravitational wave experiments, with distinctive features as parity violation and non-Gaussianity. I will explain the properties of such scenarios, and their distinctive predictions for what respect the gravity wave power spectrum and bispectrum. I will then discuss how to quantitatively test these predictions with current and future interferometers. (Conference Room San Felipe) |
10:30 - 11:30 |
Coffee Break (Conference Room San Felipe) |
11:30 - 12:00 |
Yuko Urakawa: Gravitational wave forest from string axiverse ↓ It was recently shown that axions can be a prominent source of gravitational waves. We first show that an axion which was located at a shallower region of the scalar potential than the quadratic one generically undergoes parametric resonance instability. We also studied non-linear dynamics of the axion caused by the resonance instability based on lattice simulation. We show that string axions in various mass ranges generate gravitational waves (GWs) with peaks at various frequencies determined by the mass scales, dubbed the GW forest. This may allow us to explore string axiverse through future multi-frequency GW observations. (Conference Room San Felipe) |
12:00 - 12:30 |
Diederik Roest: Attractors, Bifurcations and Curvature in Multi-field Inflation ↓ Recent years have seen the introduction of various multi-field inflationary scenarios, in which the scalar curvature plays a crucial role. We outline a simple description that unifies these different proposals. Moreover, one can easily see which dynamical attractors will dominate the late-time behaviour of the system. We demonstrate which bifurcations govern the underlying dynamics. (Conference Room San Felipe) |
12:30 - 13:00 |
Ghazal Geshnizjani: Cuscuton Bounce ↓ In general relativity producing a regular bounce entails violation of Null Energy Condition for a dynamical source in the model. That generically
indicates existence of ghosts or other instabilities. However, in cuscuton modification of gravity, the correspondence between a background
bounce and violation of Null Energy Condition for dynamical sources is broken. Cuscuton action, modifies equations of motion in Infra Red limit
allowing the background to go through a regular bounce phase. At the same time, since it does not contain any dynamical degrees of freedom, it
does not lead to ghosts or other instabilities. Here, I present a toy scenario of a regular bouncing cosmology and prove this claim (Conference Room San Felipe) |
13:20 - 13:30 |
Group Photo (Hotel Hacienda Los Laureles) |
13:30 - 15:00 |
Lunch (Restaurant Hotel Hacienda Los Laureles) |
15:00 - 15:30 |
Luisa G. Jaime: Geometric inflation ↓ We argue that the presence of an inflationary epoch is a natural, almost unavoidable, consequence of the existence of a sensible effective
action involving an infinite tower of higher-curvature corrections to the Einstein-Hilbert action. No additional fields besides the metric are
required. This correction to General Relativity has the following features: (i) its vacuum spectrum solely consists of a graviton and is ghost free,
(ii) it possesses well-behaved black hole solutions, (iii) its cosmology is well-posed as an initial value problem and, most importantly, (iv) it
has the potential to provide a late-time cosmology arbitrarily close to LCDM while, at the same time,
giving an inflationary period in the early universe with a graceful exit (Conference Room San Felipe) |
15:30 - 16:00 |
Cliff Burgess: Limitations to EFT Methods with Gravity: Turning up the Heat ↓ Effective field theory methods underpin quantum calculations with gravity, and thereby ensure the reliability of predictions for Hawking radiation or inflationary primordial fluctuations. Yet persistent concerns (like the phenomenon of secular growth in primordial fluctuations or information loss for Hawking radiation) appear to indicate a breakdown of these techniques in what ought to be a regime under good control. This talk argues that gravity indeed introduces new boundaries to the domain of validity of EFT methods, particularly at late times (where most of the puzzles seem to lie). Evidence for this picture is provided, together with remedies that come from other, more familiar, areas of physics where similar issues also arise. (Conference Room San Felipe) |
16:00 - 16:30 |
Coffee Break (Conference Room San Felipe) |
16:30 - 19:00 |
Informal Discussions (Conference Room San Felipe) |
19:00 - 21:00 |
Dinner (Restaurant Hotel Hacienda Los Laureles) |