Matteo Fasiello
A5058417591- Cosmology and Gravitation Theories
- Black Holes and Theoretical Physics
- Geophysics and Gravity Measurements
- Pulsars and Gravitational Waves Research
- Galaxies: Formation, Evolution, Phenomena
- Dark Matter and Cosmic Phenomena
- Solar and Space Plasma Dynamics
- Radio Astronomy Observations and Technology
- Astronomy and Astrophysical Research
- Particle physics theoretical and experimental studies
- Computational Physics and Python Applications
- Quantum Electrodynamics and Casimir Effect
- Advanced Differential Geometry Research
- Relativity and Gravitational Theory
- Stochastic processes and financial applications
- Differential Equations and Numerical Methods
- Astrophysics and Cosmic Phenomena
- Quantum Mechanics and Applications
- Neutrino Physics Research
- Nonlinear Differential Equations Analysis
- Astronomical Observations and Instrumentation
- Numerical methods for differential equations
- Experimental and Theoretical Physics Studies
- Geomagnetism and Paleomagnetism Studies
- Earth Systems and Cosmic Evolution
Consejo Superior de Investigaciones Científicas
2021-2024
Universidad Autónoma de Madrid
2021-2024
University of Portsmouth
2018-2024
National Research Council
2021
Stanford University
2014-2019
Kavli Institute for Particle Astrophysics and Cosmology
2015
Case Western Reserve University
2012-2015
University of Milano-Bicocca
2010
Istituto Nazionale di Fisica Nucleare, Sezione di Milano Bicocca
2010
Modifications of General Relativity leave their imprint both on the cosmic expansion history through a non-trivial dark energy equation state, and evolution cosmological perturbations in scalar tensor sectors. In particular, modification sector gives rise to notion gravitational-wave (GW) luminosity distance, different from standard electromagnetic that can be studied with sirens at GW detectors such as LISA or third-generation ground based experiments. We discuss predictions for modified...
The Laser Interferometer Space Antenna (LISA) has the potential to reveal wonders about fundamental theory of nature at play in extreme gravity regime, where gravitational interaction is both strong and dynamical. In this white paper, Fundamental Physics Working Group LISA Consortium summarizes current topics physics observations GWs can be expected provide key input. We briefest reviews then delineate avenues for future research directions discuss connections between working group, other...
Abstract We investigate the sensitivity of Laser Interferometer Space Antenna (LISA) to anisotropies Stochastic Gravitational Wave Background (SGWB). first discuss main astrophysical and cosmological sources SGWB which are characterized by in GW energy density, we build a Signal-to-Noise estimator quantify LISA different multipoles. then perform Fisher matrix analysis prospects detectability anisotropic features with for individual multipoles, focusing on power-law frequency profile. compute...
Inspired by the chromo-natural inflation model of Adshead&Wyman, we reshape its scalar content to relax tension with current observational bounds. Besides an inflaton, setup includes a spectator sector in which axion and SU(2) gauge fields are coupled via Chern-Simons-type term. The result is viable theory endowed alternative production mechanism for gravitational waves during inflation. wave signal sourced can be much larger than contribution from standard vacuum fluctuations, it...
We give a simple derivation of cosmological bound on the graviton mass for spatially flat FRW solutions in massive gravity with an reference metric and bigravity theories. This comes from requirement that kinetic term helicity zero mode is positive definite. The dependent only parameters potential Hubble expansion rate two metrics. derive decoupling limit gravity, use this to independent bound. recover our previous results tension between satisfying Friedmann equation sufficient rule out all...
With the completion of Planck mission, in order to continue gather cosmological information it has become crucial understand Large Scale Structures (LSS) universe percent accuracy. The Effective Field Theory LSS (EFTofLSS) is a novel theoretical framework that aims develop an analytic understanding at long distances, where inhomogeneities are small. We further description biased tracers EFTofLSS account for effect baryonic physics and primordial non-Gaussianities, finding new bias...
Abstract Cosmological α -attractors stand out as particularly compelling models to describe inflation in the very early universe, naturally meeting tight observational bounds from cosmic microwave background (CMB) experiments. We investigate -attractor potentials presence of an inflection point, leading enhanced curvature perturbations on small scales. study both single- and multi-field models, driven by scalar fields living a hyperbolic field space. In single-field case, ultra-slow-roll...
Abstract Gravitational wave (GW) backgrounds of cosmological origin are expected to be nearly isotropic, with small anisotropies resembling those the cosmic microwave background. We analyse case a scalar-induced GW background and clarify in process relation between two different approaches calculating anisotropies. focus on scenarios sourced by significantly peaked scalar spectrum, which frequently considered context primordial black holes production. show that resulting characterised...
Abstract We consider inflation driven by an axion-like particle coupled to SU(2) gauge sector via a Chern-Simons term. Known as chromo-natural inflation, this scenario is in tension with CMB observations. In order remedy fact and preserve both the symmetries intriguing gravitational wave phenomenology exhibited model, we explore non-minimal coupling of axion-inflaton Einstein tensor. identify regions parameter space corresponding viable cosmology at scales. also highlight possibility...
In de Sitter spacetime there exists an absolute minimum for the mass of a spin-2 field set by Higuchi bound m^2 \geq 2H^2. We generalize this to arbitrary spatially flat FRW geometries in context recently proposed ghost-free models Massive Gravity with reference metric, performing Hamiltonian analysis cosmological perturbations. find that generically indicates solutions massive gravity, which exhibit Vainshtein mechanism background as required consistency observations, imply helicity zero...
We prove that the linear instability in a non-degenerate higher derivative theory, Ostrogradski instability, can only be removed by addition of constraints if original theory's phase space is reduced.
We show that a large contribution to tensor modes during inflation can be generated by spectator scalar field with speed of sound lower than unity.Received 4 June 2013DOI:https://doi.org/10.1103/PhysRevD.88.103518© 2013 American Physical Society
Attention has focussed recently on models of inflation that involve a second or more fields with mass near the inflationary Hubble parameter H, as may occur in supersymmetric theories if supersymmetry-breaking scale is not far from H. Quasi-single-field (QsF) relatively simple family phenomenological serve proxy for additional masses m∼ Since QsF involves addition to inflaton, consistency conditions between correlations arise single-clock are necessarily satisfied. As result, correlation...
We show that every Galileon theory admits a dual formulation as with new operator coefficients. In n dimensions free scalar field in Minkowski spacetime is to (n+1)-th order which exhibits the Vainshtein mechanism when coupled sources and superluminal propagation even on-shell. This demonstrates compatible an analytic S-matrix causality. For point sources, duality interchanges strongly regime weakly asymptotic regime. The made manifest context of decoupling limit bigravity, but independent this.
With the completion of Planck mission, in order to continue gather cosmological information it has become crucial understand Large Scale Structures (LSS) universe percent accuracy. The Effective Field Theory LSS (EFTofLSS) is a novel theoretical framework that aims develop an analytic understanding at long distances, where inhomogeneities are small. We further description biased tracers EFTofLSS account for effect baryonic physics and primordial non-Gaussianities, finding new bias...
Our current understanding of the Universe is established through pristine measurements structure in cosmic microwave background (CMB) and distribution shapes galaxies tracing large scale (LSS) Universe. One key ingredient that underlies cosmological observables field sources observed assumed to be initially Gaussian with high precision. Nevertheless, a minimal deviation from Gaussianityis perhaps most robust theoretical prediction models explain Universe; itis necessarily present even...
Our current understanding of the Universe is established through pristine measurements structure in cosmic microwave background (CMB) and distribution shapes galaxies tracing large scale (LSS) Universe. One key ingredient that underlies cosmological observables field sources observed assumed to be initially Gaussian with high precision. Nevertheless, a minimal deviation from Gaussianityis perhaps most robust theoretical prediction models explain Universe; itis necessarily present even...
Characterizing the physical properties of stochastic gravitational waves background (SGWB) is a key step towards identifying nature its possible origin. We focus our analysis on SGWB anisotropies. The existence non-trivial primordial scalar-tensor-tensor (STT) correlation in squeezed configuration may be inferred from effect that long wavelength scalar mode has wave power spectrum: an anisotropic contribution. Crucially, such contribution correlated with temperature anisotropies cosmic...
The propagation speed of gravitational waves, $c_T$, has been tightly constrained by the binary neutron star merger GW170817 and its electromagnetic counterpart, under assumption a frequency-independent $c_T$. Drawing upon arguments from Effective Field Theory quantum gravity, we discuss possibility that modifications General Relativity allow for transient deviations $c_T$ light at frequencies well below band current ground-based detectors. We motivate two representative Ans\"atze $c_T(f)$,...
Abstract In this work we analyse in detail the possibility of using small and intermediate-scale gravitational wave anisotropies to constrain inflationary particle content. First, develop a phenomenological approach focusing on generated by primordial tensor-tensor-scalar purely non-Gaussianities. We highlight quantities that play key role determining detectability signal. To amplify power as probe early universe physics, consider cross-correlations with CMB temperature anisotropies. assess...
The Laser Interferometer Space Antenna (LISA) has two scientific objectives of cosmological focus: to probe the expansion rate universe, and understand stochastic gravitational-wave backgrounds their implications for early universe particle physics, from MeV Planck scale. However, range potential applications gravitational wave observations extends well beyond these objectives. This publication presents a summary state art in LISA cosmology, theory methods, identifies new opportunities use...
The anisotropies of the stochastic gravitational wave background, as produced in early phases cosmological evolution, can act a key probe primordial universe particle content. We point out new universal property origin: for adiabatic initial conditions, their angular power spectrum is insensitive to equation state cosmic fluid driving expansion before big bang nucleosynthesis. Any deviation from this behavior points presence nonadiabatic sources fluctuations. Such scenarios be tested by...
A bstract We consider inflationary models with multiple spectator axions coupled to dark gauge sectors via Chern-Simons (CS) terms. The energy injection into Abelian fields from the engenders a multi-peak profile for scalar and tensor spectra. highlight constraining power of CMB spectral distortions on signal discuss conditions under which can account recently observed stochastic gravitational wave (GW) background in nHz range. Given tantalizing prospect “GW forest” spanning several decades...