Diego Blas
A5040364332- Cosmology and Gravitation Theories
- Pulsars and Gravitational Waves Research
- Dark Matter and Cosmic Phenomena
- Black Holes and Theoretical Physics
- Noncommutative and Quantum Gravity Theories
- Geophysics and Gravity Measurements
- Galaxies: Formation, Evolution, Phenomena
- Atomic and Subatomic Physics Research
- Cold Atom Physics and Bose-Einstein Condensates
- Astrophysics and Cosmic Phenomena
- Radio Astronomy Observations and Technology
- Astronomy and Astrophysical Research
- Advanced Frequency and Time Standards
- Relativity and Gravitational Theory
- Particle physics theoretical and experimental studies
- Scientific Research and Discoveries
- Gamma-ray bursts and supernovae
- Stellar, planetary, and galactic studies
- Advanced Differential Geometry Research
- Astrophysical Phenomena and Observations
- Neutrino Physics Research
- Geophysics and Sensor Technology
- Advanced Thermodynamics and Statistical Mechanics
- Orbital Angular Momentum in Optics
- Computational Physics and Python Applications
Institute for High Energy Physics
2022-2025
Barcelona Institute for Science and Technology
2022-2025
Institució Catalana de Recerca i Estudis Avançats
2024-2025
Shanghai Institute for Science of Science
2024-2025
Institute of Science and Technology
2024-2025
Universitat Autònoma de Barcelona
2022-2024
Centre de Recerca Matemàtica
2023-2024
Institut Català de Ciències del Clima
2024
King's College London
2018-2024
University College London
2019-2022
Boltzmann codes are used extensively by several groups for constraining cosmological parameters with Cosmic Microwave Background and Large Scale Structure data. This activity is computationally expensive, since a typical project requires from 10'000 to 100'000 code executions. The newly released CLASS (Cosmic Linear Anisotropy Solving System) incorporates improved approximation schemes leading simultaneous gain in speed precision. We describe here the three approximations basic LambdaCDM...
We propose a natural extension of Horava's model for quantum gravity, which is free from the notorious pathologies original proposal. The new endows scalar graviton mode with regular quadratic action and remains power-counting renormalizable. At low energies, it reduces to Lorentz-violating scalar-tensor gravity theory. deviations respect general relativity can be made weak by an appropriate choice parameters.
Hořava's proposal for non-relativistic quantum gravity introduces a preferred time foliation of space-time which violates the local Lorentz invariance. The is encoded in dynamical scalar field we call 'khronon'. dynamics khronon sensitive to symmetries and other details particular implementations proposal. In this paper examine several consistency issues present three theories: projectable theory, healthy non-projectable extension, new extension related ghost condensation. We find that only...
The exploration of the universe has recently entered a new era thanks to multi-messenger paradigm, characterized by continuous increase in quantity and quality experimental data that is obtained detection various cosmic messengers (photons, neutrinos, rays gravitational waves) from numerous origins. They give us information about their sources properties intergalactic medium. Moreover, astronomy opens up possibility search for phenomenological signatures quantum gravity. On one hand, most...
We outline the experimental concept and key scientific capabilities of AION (Atom Interferometer Observatory Network), a proposed programme using cold strontium atoms to search for ultra-light dark matter, explore gravitational waves in mid-frequency range between peak sensitivities LISA LIGO/Virgo/ KAGRA/INDIGO/Einstein Telescope/Cosmic Explorer experiments, probe other frontiers fundamental physics. would complement planned searches as well mergers involving intermediate-mass black holes...
Abstract We propose in this White Paper a concept for space experiment using cold atoms to search ultra-light dark matter, and detect gravitational waves the frequency range between most sensitive ranges of LISA terrestrial LIGO/Virgo/KAGRA/INDIGO experiments. This interdisciplinary experiment, called Atomic Experiment Dark Matter Gravity Exploration (AEDGE), will also complement other planned searches exploit synergies with wave detectors. give examples extended sensitivity matter offered...
The grand challenges of contemporary fundamental physics---dark matter, dark energy, vacuum inflation and early universe cosmology, singularities the hierarchy problem---all involve gravity as a key component. And all gravitational phenomena, black holes stand out in their elegant simplicity, while harbouring some most remarkable predictions General Relativity: event horizons, ergoregions. hitherto invisible landscape Universe is being unveiled before our eyes: historical direct detection...
Binary pulsars are ideal to test the foundations of General Relativity, such as Lorentz symmetry, which requires that experiments produce same results in all free-falling (i.e.inertial) frames. We here break this symmetry gravitational sector by specifying a preferred time direction, and thus frame, at each spacetime point. then examine consequences breaking orbital evolution binary pulsars, focusing on dissipative effects. find modifies these effects, dynamics, two different ways. First, it...
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...
New light states thermally coupled to the Standard Model plasma alter expansion history of Universe and impact synthesis primordial elements. In this work, we carry out an exhaustive precise analysis implications MeV-scale BSM particles in Big Bang Nucleosynthesis (BBN) for Cosmic Microwave Background (CMB) observations. We find that BBN observations set a lower bound on thermal dark matter mass mχ > 0.4 MeV at 2σ. This is independent spin number internal degrees freedom particle,...
Bosonic ultra-light dark matter (ULDM) would form cored density distributions at the center of galaxies. These cores, seen in numerical simulations, admit analytic description as lowest energy bound state solution ("soliton") Schroedinger-Poisson equations. Numerical simulations ULDM galactic halos found empirical scaling relations between mass large-scale host halo and central soliton. We discuss how simulation results different groups can be understood terms basic properties Importantly,...
We give a detailed treatment of electromagnetic signals generated by gravitational waves (GWs) in resonant cavity experiments. Our investigation corrects and builds upon previous studies carefully accounting for the gauge dependence relevant quantities. work preferred frame laboratory, proper detector frame, show how to resum short-wavelength effects provide analytic results that are exact GWs arbitrary wavelength. This formalism allows us firmly establish that, contrary claims, experiments...
If dark matter is composed of axions, then axion stars form in the cores halos. These are unstable above a critical mass, decaying to radio photons that heat intergalactic medium, offering new channel for indirect detection. We recently provided first accurate calculation decay rate due star mergers. In this work we show how existing data concerning CMB optical depth leads strong constraints on photon coupling mass range <a:math xmlns:a="http://www.w3.org/1998/Math/MathML"...
Solitons are observed to form in simulations of dark matter (DM) halos consisting bosonic fields. We use the extended Press-Schechter formalism compute mass function solitons, assuming various forms for relationship between halo and soliton mass. further provide a new calculation rate major mergers. composed axion DM unstable above critical mass, decay either relativistic axions or photons, depending on values coupling constants. computed merger predict enhanced due instability. For certain...
This document presents a summary of the 2023 Terrestrial Very-Long-Baseline Atom Interferometry Workshop hosted by CERN. The workshop brought together experts from around world to discuss exciting developments in large-scale atom interferometer (AI) prototypes and their potential for detecting ultralight dark matter gravitational waves. primary objective was lay groundwork an international TVLBAI proto-collaboration. collaboration aims unite researchers different institutions strategize...
We use time-sliced perturbation theory (TSPT) to give an accurate description of the infrared non-linear effects affecting baryonic acoustic oscillations (BAO) present in distribution matter at very large scales. In TSPT this can be done via a systematic resummation that has simple diagrammatic representation and does not involve uncontrollable approximations. discuss power counting rules derive explicit expressions for resummed spectrum up next-to leading order bispectrum order. The...
We show that, contrary to the claim made in arXiv:0911.1299, extended Horava gravity model proposed arXiv:0909.3525 does not suffer from a strong coupling problem. By studying observational constraints on we determine bounds scale of ultraviolet modification for which proposal yields phenomenologically viable, renormalizable and weakly coupled quantum gravity.
Under broad assumptions breaking of Lorentz invariance in gravitational theories leads to tension with unitarity because it allows for processes that apparently violate the second law thermodynamics. The crucial ingredient this argument is existence black hole solutions interior shielded from infinity by a causal horizon. We study how paradox can be resolved healthy extension Horava gravity. To aim we analyze classical describing large holes theory emphasis on their structure. notion...
Binary pulsars are excellent laboratories to test the building blocks of Einstein's theory general relativity. One these is Lorentz symmetry, which states that physical phenomena appear same for all inertially moving observers. We study effect violations symmetry in orbital evolution binary and find it induces a much more rapid decay binary's period due emission dipolar radiation. The absence such behavior recent observations allows us place most stringent constraints on violation gravity,...
We prove perturbative renormalizability of projectable Horava gravity. The key element the argument is choice a gauge which ensures correct anisotropic scaling propagators and their uniform falloff at large frequencies momenta. This guarantees that counterterms required to absorb loop divergences are local marginal or relevant with respect scaling. Gauge invariance achieved by making use background-covariant formalism. also comment on difficulties this approach when addressing non-projectable model.
We consider the scenario where dark matter (DM) is represented by an ultralight classical scalar field performing coherent periodic oscillations. point out that such DM perturbs dynamics of binary systems either through its gravitational or via direct coupling to ordinary matter. This perturbation gets resonantly amplified if frequency oscillations close a (half-)integer multiple orbital system and leads secular variation period. suggest using pulsars as probes this estimate their...