242 citations · 1.1k across the 28 of their papers we have counts for
28 papers
Gauge versus (hidden) physical symmetries of FLRW cosmologies
Andrea Calcinari, Adrià Delhom, Federico Greco +2
In generally covariant theories, evolution in coordinate time is a gauge transformation, so that a symmetry made manifest in a gauge-fixed description need not be a symmetry of the…
Collective excitations in quantum gravity condensates
Andrea Calcinari, Adrià Delhom, Daniele Oriti
A central open problem in quantum gravity is to understand how continuum spacetime emerges from quantum-geometric degrees of freedom in a background-independent setting. A many-bod…
Analogue gravity with Bose-Einstein condensates
Adrià Delhom, Luca Giacomelli
Analogue gravity explores how collective excitations in condensed matter systems can reproduce the behavior of fields in curved spacetimes. An important example is the acoustic bla…
Toward the Observation of Entangled Pairs in BEC analogue Expanding Universes
Ivan Agullo, Adrià Delhom, Álvaro Parra-López
Pair creation is a fundamental prediction of quantum field theory in curved spacetimes. While classical aspects of this phenomenon have been observed, the experimental confirmation…
Polariton Fluids as Quantum Field Theory Simulators on Tailored Curved Spacetimes
Kévin Falque, Adrià Delhom, Quentin Glorieux +3
Quantum fields in curved spacetime exhibit a wealth of effects like Hawking radiation from black holes. While quantum field theory in black holes can only be studied theoretically,…
Entanglement from superradiance and rotating quantum fluids of light
Adrià Delhom, Killian Guerrero, Paula Calizaya +5
The amplification of radiation by superradiance is a universal phenomenon observed in numerous physical systems. We demonstrate that superradiant scattering generates entanglement…
Entanglement from rotating black holes in thermal baths
Ivan Agullo, Anthony J. Brady, Adrià Delhom +1
We extend previous efforts to quantify the entanglement generated in Hawking's evaporation process by including rotation and thermal environments (e.g. the cosmic microwave backgro…
A diffeomorphism invariant family of metric-affine actions for loop cosmologies
Adrià Delhom, Gonzalo J. Olmo, Parampreet Singh
In loop quantum cosmology (LQC) the big bang singularity is generically resolved by a big bounce. This feature holds even when modified quantization prescriptions of the Hamiltonia…
Bootstrapping gravity and its extension to metric-affine theories
Adrià Delhom, Gerardo García-Moreno, Manuel Hohmann +2
In this work we study diffeomorphism-invariant metric-affine theories of gravity from the point of view of self-interacting field theories on top of Minkowski spacetime (or other b…
Instabilities in field theories: Lecture notes with a view into modified gravity
Adrià Delhom, Alejandro Jiménez-Cano, Francisco José Maldonado Torralba
Modified theories of gravity usually present new degrees of freedom, as well as higher order derivatives, wrong signs in certain terms and complicated couplings already present in…
Spontaneous Lorentz symmetry breaking and one-loop effective action in the metric-affine bumblebee gravity
Adrià Delhom, T. Mariz, J. R. Nascimento +3
The metric-affine bumblebee model in the presence of fermionic matter minimally coupled to the connection is studied. We show that the model admits an Einstein frame representation…
Theoretical and Observational Aspecs in Metric-Affine Gravity: A field theoretic perspective
Adrià Delhom
In this PhD thesis we deal with several theoretical and phenomenological apsects of metric-affine theories of gravity. Concretely, we first give a broad introduction to the necessa…
Modified Gravity and Cosmology: An Update by the CANTATA Network
Emmanuel N. Saridakis, Ruth Lazkoz, Vincenzo Salzano +50
General Relativity and the CDM framework are currently the standard lore and constitute the concordance paradigm. Nevertheless, long-standing open theoretical issues, as well as…
Born-Infeld Gravity: Constraints from Light-by-Light Scattering and an Effective Field Theory Perspective
Jose Beltrán Jiménez, Adrià Delhom, Gonzalo J. Olmo +1
By using a novel technique that establishes a correspondence between general relativity and metric-affine theories based on the Ricci tensor, we are able to set stringent constrain…
Radiative corrections in metric-affine bumblebee model
Adrià Delhom, J. R. Nascimento, Gonzalo J. Olmo +2
We consider the metric-affine formulation of bumblebee gravity, derive the field equations, and show that the connection can be written as Levi-Civita of a disformally related metr…
Comment on "Einstein-Gauss-Bonnet Gravity in Four-Dimensional Spacetime"
Julio Arrechea, Adrià Delhom, Alejandro Jiménez-Cano
We argue that several statements in Phys. Rev. Lett. 124, 081301 (2020) are not correct.
Anisotropic deformations in a class of projectively-invariant metric-affine theories of gravity
Jose Beltrán Jiménez, Daniel de Andrés, Adrià Delhom
Among the general class of metric-affine theories of gravity, there is a special class conformed by those endowed with a projective symmetry. Perhaps the simplest manner to realise…
Instabilities in Metric-Affine Theories of Gravity
Jose Beltrán Jiménez, Adrià Delhom
We discuss the presence of ghostly instabilities for metric-affine theories constructed with higher order curvature terms. We mainly focus on theories containing only the Ricci ten…
Inconsistencies in four-dimensional Einstein-Gauss-Bonnet gravity
Julio Arrechea, Adrià Delhom, Alejandro Jiménez-Cano
We attempt to clarify several aspects concerning the recently presented four-dimensional Einstein-Gauss-Bonnet gravity. We argue that the limiting procedure outlined in [Phys. Rev.…
Minimal coupling in presence of non-metricity and torsion
Adrià Delhom
We deal with the question of what it means to define a minimal coupling prescription in presence of torsion and/or non-metricity, carefully explaining while the naive substitution…
Conformally invariant proper time with general non-metricity
Adria Delhom, Iarley P. Lobo, Gonzalo J. Olmo +1
We show that the definition of proper time for Weyl-invariant space-times given by Perlick naturally extends to spaces with arbitrary non-metricity. We then discuss the relation be…
Metric-affine bumblebee gravity: classical aspects
Adria Delhom, J. R. Nascimento, Gonzalo J. Olmo +2
We consider the metric-affine formulation of bumblebee gravity, derive the field equations, and show that the connection can be written as Levi-Civita of a disformally related metr…
Ricci-Based Gravity theories and their impact on Maxwell and nonlinear electromagnetic models
Adria Delhom, Gonzalo J. Olmo, Emanuele Orazi
We extend the correspondence between metric-affine Ricci-Based Gravity theories and General Relativity (GR) to the case in which the matter sector is represented by linear and nonl…
Effective interactions in Ricci-Based Gravity models below the non-metricity scale
Adria Delhom, Victor Miralles, Ana Peñuelas
We show how minimally-coupled matter fields of arbitrary spin, when coupled to Ricci-Based Gravity theories, develop non-trivial effective interactions that can be treated perturba…