A5035407296- Cosmology and Gravitation Theories
- Black Holes and Theoretical Physics
- Pulsars and Gravitational Waves Research
- Geophysics and Gravity Measurements
- Solar and Space Plasma Dynamics
- Dark Matter and Cosmic Phenomena
- Galaxies: Formation, Evolution, Phenomena
- Particle physics theoretical and experimental studies
- Quantum chaos and dynamical systems
- Advanced Thermodynamics and Statistical Mechanics
- Radio Astronomy Observations and Technology
- Theoretical and Computational Physics
- Earth Systems and Cosmic Evolution
- Relativity and Gravitational Theory
- Quantum and electron transport phenomena
- Economic Theory and Policy
- Complex Systems and Time Series Analysis
- Spaceflight effects on biology
- Spectroscopy and Quantum Chemical Studies
- Stochastic processes and financial applications
- Fluid Dynamics and Turbulent Flows
Universitat de Barcelona
2024
Institut d'Astrophysique de Paris
2019-2023
Universidad Autónoma de Madrid
2022-2023
Sorbonne Université
2019-2022
Centre National de la Recherche Scientifique
2019-2022
Consejo Superior de Investigaciones Científicas
2022
National Institute for Subatomic Physics
2016-2018
University of Geneva
2014
We identify a characteristic pattern in the scalar-induced stochastic gravitational wave background from particle production during inflation. If is sufficiently efficient, scalar power spectrum exhibits (1) oscillations periodic k, of sharp feature, with an exponentially enhanced envelope. systematically study properties induced waves sourced after inflation and find that this inherits structure resulting peak energy density (10 %) modulations. The frequency oscillation determined by scale...
We propose a new model-independent mechanism for producing primordial black holes from period of multi-field inflation. This requires an enhancement fluctuations at short scales compared to their value CMB scales. show that such amplification naturally occurs when the inflationary trajectory exhibits strong turn, is limited during which strongly deviates geodesic in field space, and sufficient subsequently with abundance be all or fraction dark matter. Our generic models inflation realized...
Abstract We show that, whenever the perturbations of some field are excited during inflation by a physical process on sub-horizon scales, they unavoidably generate, even through gravitational interactions alone, significant resonant IR cascade power down to scales that order horizon at time (we denote these as near IR). provide general analytic one-loop results for enhancement curvature perturbation generated this effect, highlighting role played resonance. then study number examples in...
A bstract We prove explicitly the absence of one-loop corrections to large scales from small in transient non-slow-roll dynamics. Specifically, we address loop primordial power spectrum, relative tree-level, that are independent ratio between two scales. review all necessary components, adapted our context, express diagrams as three-point functions, emphasizing crucial role played by quartic interactions. Notably, include Hamiltonian induced cubic Lagrangian and interactions ensured...
Cosmic inflation provides a window to the highest energy densities accessible in nature, far beyond those achievable any realistic terrestrial experiment. Theoretical insights into inflationary era and its observational probes may therefore shed unique light on physical laws underlying our universe. This white paper describes current theoretical understanding of era, with focus statistical properties primordial fluctuations. In particular, we survey targets for three important signatures...
We show that a scalar excited state with large occupation numbers during inflation leads to an enhancement of tensor modes and characteristic pattern order-one oscillations in the associated stochastic gravitational wave background (SGWB) sourced inflation. An effective state, i.e. departure from Bunch-Davies vacuum, can emerge dynamically as result transient non-adiabatic evolution, e.g. sharp feature along inflationary history. provide explicit example multifield context where triggering...
We show that one-loop corrections to the large-scale power spectrum from small-scale modes in non-slow-roll dynamics are always negligible, namely they volume suppressed by ratio of short long distance scales. One-loop contributions proportional wavelength tree-level spectrum, and not sharing this suppression, appear only when considering a subset vertexes, but cancel exactly all relevant interactions taken into account. prove previous statement two different ways, i.e. using equivalent...
Several recent proposals to embed inflation into high-energy physics rely on inflationary dynamics characterized by a strongly non-geodesic motion in negatively curved field space. This naturally leads transient instability of perturbations sub-Hubble scales, and their exponential amplification. Supported first-principle numerical computations, the analytical insight provided effective theory inflation, we show that bispectrum is enhanced flattened configurations, argue an analogous result...
We analyse the post-inflationary contribution to stochastic gravitational wave background due a resonant feature in scalar power spectrum, which is characterised by an oscillation log(k), complementing our previous work arXiv:2012.02761 on sharp features. Primordial features signal departures of inflation from single-field slow-roll paradigm and are motivated embeddings high energy physics. find that spectrum leads corresponding modulation can be understood as superposition two oscillatory...
Abstract Oscillations in the frequency profile of scalar-induced contribution to stochastic gravitational wave background are a characteristic signal for small-scale features during inflation. We investigate how this oscillatory is affected by expansion history post-inflationary universe. Our results applicable as long equation state universe can be taken constant period which waves produced, and we compute spectrum induced both sharp resonant features, associated with oscillations k log( ),...
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...
Abstract Various scenarios of cosmic inflation enhance the amplitude stochastic gravitational wave background (SGWB) at frequencies detectable by LISA detector. We develop tools for a template-based analysis SGWB and introduce template databank to describe well-motivated signals from inflation, prototype their searches, forecast reconstruction with LISA. Specifically, we classify seven templates based on signal frequency shape, identify representative fundamental physics models leading them....
The predictions of Standard Model Higgs inflation are in excellent agreement with the Planck data, without need for new fields. However, consistency theory requires presence (unknown) threshold corrections. These modify running couplings, and thereby change shape inflationary potential. This raises question how sensitive CMB parameters to UV completion. We show that, due a precise cancellation, almost unaffected. implies general that one cannot relate spectral index tensor-to-scalar ratio...
We propose a new model-independent mechanism for producing primordial black holes from period of multi-field inflation. This requires an enhancement fluctuations at short scales compared to their value CMB scales. show that such amplification naturally occurs when the inflationary trajectory exhibits strong turn, is limited during which strongly deviates geodesic in field space, and sufficient subsequently with abundance be all or fraction dark matter. Our generic models inflation realized...
Oscillations in the frequency profile of stochastic gravitational wave background are a characteristic prediction small-scale features during inflation. In this paper we present first investigation detection prospects such oscillations with upcoming space-based observatory LISA. As proof principle, show for selection feature signals that can be reconstructed LISA, employing method based on principal component analysis. We then perform Fisher forecast parameters describing oscillatory signal....
A bstract The measured Standard Model parameters lie in a range such that the Higgs potential, once extrapolated up to high scales, develops minimum of negative energy density. This has important cosmological implications. In particular, during inflation, quantum fluctuations could have pushed field beyond its potential barrier, triggering formation anti-de Sitter regions, with fatal consequences for our universe. By requiring this did not happen, one can principle connect (and constrain)...
Many early universe scenarios predict an enhancement of scalar perturbations at scales currently unconstrained by cosmological probes. These source gravitational waves (GWs) second order in perturbation theory, leading to a scalar-induced wave (SIGW) background. The LISA detector, sensitive mHz GWs, will be able constrain curvature new window corresponding $k \in [10^{10}, 10^{14}] \,{\rm Mpc}^{-1}$, difficult probe otherwise. In this work, we forecast the capabilities SIGWs using different...
The large class of inflationary models known as $\alpha$- and $\xi$-attractors gives identical cosmological predictions at tree level (at leading order in inverse power the number efolds). Working with renormalization group improved action, we show that these are robust under quantum corrections. This means for all considered parameters $(n_s,r)$ (nearly) independent on Renormalization Group flow. result follows once field dependence scale, fixed by demanding log correction to vanish,...
A bstract In new Higgs inflation the kinetic terms are non-minimally coupled to Einstein tensor, allowing field play role of inflaton. The interaction is non-renormalizable, and model only describes physics below some cutoff scale. Even if unknown UV does not affect tree level inflaton potential significantly, it may still enter at loop modify running Standard Model (SM) parameters. This analogous what happens in original for inflation. key difference, though, that inflationary predictions...
We study the ghost-free bimetric theory of Hassan and Rosen, with parameters β i such that a flat Minkowski solution exists for both metrics. show that, expanding around this eliminating one two metrics its own equation motion, remaining metric is governed by Einstein-Hilbert action plus non-local term proportional to W μνρσ (□ − m 2)−1 , where Weyl tensor. The result valid quadratic order in perturbation all orders derivative expansion. This example shows, simple setting, how extensions GR...
A bstract Most of the inflationary models that are in agreement with Planck data rely on presence non-renormalizable operators. If connection to low energy particle physics is made, renormalization group (RG) introduces a sensitivity ultraviolet (UV) can be crucial determining predictions. We analyse this effect for Standard Model (SM) augmented non-minimal derivative couplings gravity. Our set-up reduces SM small values Higgs field, and allows inflation opposite large field regime. The...
We summarize progress made in theoretical astrophysics and cosmology over the past decade areas of interest for coming decade. This Report is prepared as TF09 "Astrophysics Cosmology" topical group summary Theory Frontier part Snowmass 2021 process.
A disformal transformation is a very useful tool to analyze general effective theory description of inflation. It can for example be used set the tensor sound speed unity, such that power spectrum only depends on Hubble parameter. However, has also led quite some confusion in recent literature. We hope clarify by pointing out nothing else than change units. show how everything achieved (possibly time-dependent) transformation, equally follows from equivalent units, up all orders perturbation...