The Cosmic Microwave Background (CMB) temperature and polarization anisotropy measurements from the Planck mission have provided strong confirmation of the LCDM model of structure formation.

However, there are a few interesting tensions with other cosmological probes and anomalies in the data that leave the door open to possible extensions to LCDM. The most famous ones are the Hubble constant and the S8 parameter tensions, the Alens anomaly and a curvature of the Universe.

I will review all of them, showing some interesting extended cosmological scenarios, in order to find a new concordance model that could explain the current cosmological data.

Cosmological tensions are of fundamental importance. Despite the increase in the precision and amount of data, the theory of Cosmology remains essentially the same as it has been for the last two decades. These tensions between measurements of the early and late Universe are at present the only existing hint of new physics in Cosmology.

I will discuss methods to quantify tension. I will propose the `Suspiciousness’ statistic as the best metric of tension for cosmological problems, as it consists of fully Bayesian quantities, and does not depend on the prior volume. I will also discuss how this metric can be used for internal consistency tests, which are fundamental for present and future cosmological surveys. I will finally use this method to quantify consistency between existing data sets such as Planck, DES, BOSS, ACTpol and SPTpol.

A detection of the stochastic gravitational-wave background (SGWB) from unresolved compact binary coalescences could be made by Advanced LIGO and Advanced Virgo at their design sensitivities. However, it is possible for magnetic noise that is correlated between spatially separated ground-based detectors to mimic a SGWB signal. Realistic simulations are used to show that this method prevents a false SGWB detection due to correlated magnetic noise.

I will present the results of a new statistical analysis of the LIGO-Virgo catalogue of merging binary black holes to test the proposition that the sources are primordial black hole (PBH) mergers. I will discuss recent predictions for the merger rate of PBHs formed from a peak in the small-scale primordial curvature power spectrum, and show that such models are decisively disfavoured compared with simple models of stellar black hole mergers. I will argue that a successful PBH model must either modify the lognormal shape of the initial mass function significantly or abandon the hypothesis that all observed merging binaries are primordial.

A talk on recent work comparing the PBH mass distribution with different calculations and assumptions, and calculating robust constraints on the power spectrum taking into account subtleties in the PBH calculation

The detection and characterisation of primordial gravitational waves produced during inflation can be an excellent test for the particle content of the very early universe. We consider an inflationary realisation whose tensor spectrum is sourced already at linear order, with a sufficient production of primordial gravitational waves to make the signal detectable at interferometer scales. We then focus on the tensor non-Gaussianities that ensue from the same configuration. On small-scales, anisotropies induced in the tensor power spectrum by long-short modes coupling become the key handle on (squeezed) primordial non-Gaussianities. We identify the parameter space generating percent level anisotropies at scales soon to be probed by SKA and LISA.

The bispectrum is the leading non-Gaussian statistic in Large-Scale Structure (LSS) clustering and encodes the interactions in the underlying field. It thus is an important diagnostic for primordial non-Gaussianity and higher order galaxy biasing.

In this paper we present a detailed test and calibration of the matter bispectrum counterterms in the Effective Field Theory of LSS against a suite of N-body simulations. We are going beyond previous studies in employing realization based perturbation theory that allows for a significant reduction in cosmic variance error bars. This enables the measurement of the low-energy constants on large scales, before two-loop corrections become relevant around k<0.09 Mpc/h at z=0. We also go beyond previous work in using bispectrum propagator terms, i.e. correlators with linear and second order fields, to quantify the two new counterterms in isolation and to establish consistency with the power spectrum counterterm.

By investigating the fully non-linear bispectrum, Bnnn, as well as the terms Bn11 and Bn21, we find evidence for the new counterterms deviating from the shape suggested by the UV-limit of the relevant bispectrum contribution.

We also show that the commonly used Einstein-de Sitter approximation for the tree level bispectrum is insufficient for precise studies of the one-loop bispectrum and that it is necessary to use LCDM growth factors in order to obtain meaningful one-loop counterterm constraints. Finally, we also find evidence for small deviations in the growth factors that arise from integration inaccuracies in the N-body simulations.

Over the last decade, the EFTofLSS has emerged as a front-runner in the modeling of cosmological statistics, providing fast highly-accurate models of the galaxy power spectrum and beyond. But what lies ahead for the theory? In this talk I will discuss some recent applications of the EFTofLSS: cosmological parameter estimation from galaxy surveys (including H0 constraints); modeling alternative density statistics; and synergies with the halo model, providing a path for precision analysis of weak-lensing spectra. This is based on arXiv: 2002.04035, 2008.08084, 2004.09515 & 2006.10055.

The unitarity of time evolution, or colloquially the conservation of probability, sits at the heart of our descriptions of fundamental interactions via quantum field theory. The implications of unitarity for scattering amplitudes are well understood, for example through the optical theorem and cutting rules. In contrast, the implications for in-in correlators in curved spacetime and the associated wavefunction of the universe, which are measured by cosmological surveys, are much less understood. For fields of any mass in de Sitter spacetime with general local interactions, which need not be invariant under de Sitter isometries, we show that unitarity implies an infinite set of relations among the coefficients \psi_{n} of the wavefunction of the universe with n fields, which we name Cosmological Optical Theorem. For contact diagrams, our result dictates the analytic structure of \psi_{n} and strongly constrains its form. For example, any correlator with an odd number of conformally-coupled scalar fields and any number of massless scalar fields must vanish. For four-point exchange diagrams, the Cosmological Optical Theorem yields a simple and powerful relation between \psi_{3} and \psi_{4}, or equivalently between the bispectrum and trispectrum. As explicit checks of this relation, we discuss the trispectrum in single-field inflation from graviton exchange and self-interactions. Moreover, we provide a detailed derivation of the relation between the total-energy pole of cosmological correlators and flat-space amplitudes. We provide analogous formulae for sub-diagram singularities. Our results constitute a new, powerful tool to bootstrap cosmological correlators.

I will discuss recent results from full-blown numerical relativity simulations of early-universe scenarios, demonstrating that slow contraction is a “supersmoothing” cosmological phase that homogenizes, isotropizes and flattens the universe and can do so far more robustly and rapidly than had been realized in earlier studies.

Single-field slow-roll Inflation has proven to be a model that has passed both numerous observational tests and theoretical scrutiny. Nevertheless, the assumption of a single inflaton, is both unphysical and not motivated by higher energy theories, leading to the need for an introduction of a scalar multiplet, possibly with non-trivial kinetic terms. In this work, we focus on the Hyperinflation model and provide a consice treatment of the evolution of the entropic and adiabatic perturbations on the curved field-space background. We provide bounds for the cosmological observables related to this model and draw comparisons with observational data which leads to restrictions in the admissible values of the field-space curvature parameter.

UV luminosity functions provide a wealth of information on the physics of galaxy formation in the early Universe. Given that this probe indirectly tracks the evolution of the mass function of dark matter halos, it has the potential to constrain alternative theories of structure formation. One of such scenarios is the existence of primordial non-Gaussianity at scales beyond those probed by observations of the Cosmic Microwave Background. Through its impact on the halo mass function, such small-scale non-Gaussianity would alter the abundance of galaxies at high redshifts. In this work we present an application of UV luminosity functions as measured by the Hubble Space Telescope to constrain the non-Gaussianity parameter f_NL for wavenumbers above a cut-off scale k_cut.