252 citations · 1.5k across the 51 of their papers we have counts for
52 papers
Accelerating scaling solutions from dark matter particle creation
Sudip Halder, Jaume de Haro, Supriya Pan +3
This article opens new window to obtain accelerating scaling attractors without any need of dark energy. We study cosmological dynamics in a two-fluid system where pressureless dar…
A dynamical approach to General Relativity based on proper time
Jaume de Haro
This work places the invariant at the center of the gravitational interaction, interpreting it not as a purely geometric object but as the differential of proper time, endow…
Novikov Coordinates and the Physical Description of Gravitational Collapse
Jaume de Haro
We show that the Novikov coordinates can be obtained in a direct and physically transparent way from the radial geodesics of massive particles with negative energy in the Schwarzsc…
Recovering Einstein Mature View of Gravitation: A Dynamical Reconstruction Grounded in the Equivalence Principle
Jaume de Haro, Emilio Elizalde
The historical and conceptual foundations of General Relativity are revisited, putting the main focus on the physical meaning of the invariant ds, the Equivalence Principle, and th…
Is Gravity Truly Balanced? A Historical-Critical Journey Through the Equivalence Principle and the Genesis of Spacetime Geometry
Jaume de Haro, Emilio Elizalde
We present a novel derivation of the spacetime metric generated by matter, without invoking Einstein's field equations. For static sources, the metric arises from a relativistic fo…
On the Geometric Meaning of General Relativity and the Foundations of Newtonian Cosmology
Jaume de Haro, Emilio Elizalde
The geometric foundations of General Relativity are revisited, with particular attention to its gauge invariance, as a key to understanding the true nature of spacetime. Beyond the…
Is Dark Energy an Effective Manifestation of Non-equilibrium Thermodynamics? -- Insights from DESI
Sauvik Bhattacharjee, Sudip Halder, Jaume de Haro +2
We investigate the background cosmological expansion on the onset of cosmological homogeneous matter creation scenario, a dynamical dark matter approach (), and…
On the perturbed Friedmann equations in Newtonian Gauge
Jaume de Haro, Emilio Elizalde, Supriya Pan
Based on the Newtonian mechanics, in this article, we present a heuristic derivation of the Friedmann equations, providing an intuitive foundation for these fundamental relations i…
Gravitational reheating formulas and bounds in oscillating backgrounds
Jaume de Haro, Llibert Aresté Saló, Supriya Pan
In this article we calculate the reheating temperature in the cosmological scenarios where heavy scalar particles are gravitationally produced, due to a conformally coupled interac…
Gravitational reheating formulas and bounds in oscillating backgrounds II: Constraints on the spectral index and gravitational dark matter production
Jaume de Haro, Supriya Pan
The reheating temperature plays a crucial role in the early universe's evolution, marking the transition from inflation to the radiation-dominated era. It directly impacts the numb…
Relations between Newtonian and relativistic cosmology
Jaume de Haro
We start with the cosmic Friedmann equations, where we adopt a novel perspective rooted in a Lagrangian formulation grounded in Newtonian mechanics and the first law of thermodynam…
Phase space analysis of sign-shifting interacting dark energy models
Sudip Halder, Jaume de Haro, Tapan Saha +1
The theory of non-gravitational interaction between a pressure-less dark matter (DM) and dark energy (DE) is a phenomenologically rich cosmological domain which has received magnif…
On the Hole Argument and the physical interpretation of General Relativity
Jaume de Haro
Einstein presented the Hole Argument against General Covariance, understood as invariance with respect to a change of coordinates, as a consequence of his initial failure to obtain…
Finite-time Cosmological Singularities and the Possible Fate of the Universe
Jaume de Haro, Shin'ichi Nojiri, S. D. Odintsov +2
Singularities in any physical theory are either remarkable indicators of the unknown underlying fundamental theory, or indicate a change in the description of the physical reality.…
Reheating formulas in Quintessential Inflation via Gravitational Particle Production
Jaume de Haro
We calculate the reheating temperature in scenarios where heavy particles are gravitationally produced during a phase transition. We explore two distinct situations: the decay of t…
Reheating constraints in Instant Preheating
Jaume de Haro
We use Instant Preheating as a mechanism to reheat the universe when its evolution is modeled by a non-oscillating background. Once we obtain the reheating temperature, we calculat…
An analytic formula to calculate the reheating temperature via gravitational particle production
Jaume de Haro, Llibert Aresté Saló
We present for smooth non-oscillating backgrounds an analytic formula which calculates the energy density of massive and massless particles created via gravitational particle produ…
The problem of calculating the -Bogoliubov coefficient in Non-Oscillating models
Jaume de Haro, Llibert Aresté Saló
The calculation of the Bogoliubov coefficients is a key piece to obtain the reheating temperature of the Universe. In all cases this calculation is performed either in toy models w…
Gravitational particle production of superheavy massive particles in Quintessential Inflation II: -attractors
Llibert Aresté Saló, Jaume de Haro
We compute the gravitational production of conformally coupled superheavy particles during the phase transition from the end of inflation to the beginning of kination for -attra…
A review of Quintessential Inflation
Jaume de Haro, Llibert Aresté Saló
We compute numerically the reheating temperature due to the gravitational production of conformally coupled superheavy particles during the phase transition from the end of inflati…
Theoretical and observational bounds on some interacting vacuum energy scenarios
Weiqiang Yang, Supriya Pan, Llibert Aresté Saló +1
The dynamics of interacting dark matter-dark energy models is characterized through an interaction rate function quantifying the energy flow between these dark sectors. In most of…
Understanding the phenomenology of interacting dark energy scenarios and their theoretical bounds
Supriya Pan, Jaume de Haro, Weiqiang Yang +1
Non-gravitational interaction between dark matter and dark energy has been considered in a spatially flat Friedmann-Lemaître-Robertson-Walker (FLRW) universe. The interaction rate…
Understanding gravitational particle production in quintessential inflation
Jaume de Haro, Supriya Pan, Llibert Aresté Saló
The diagonalization method, introduced by a group of Russian scientists at the beginning of seventies, is used to compute the energy density of superheavy massive particles produce…
Authenticating the Presence of a Relativistic Massive Black Hole Binary in OJ 287 Using its General Relativity Centenary Flare: Improved Orbital Parameters
Lankeswar Dey, M. J. Valtonen, A. Gopakumar +5
Results from regular monitoring of relativistic compact binaries like PSR 1913+16 are consistent with the dominant (quadrupole) order emission of gravitational waves (GWs). We show…