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Alberto Fritis Puga (Universidad de la Serena)
Horizon thermodynamics constitutes an interesting area of research in the context of gravitation. This rela- tionship has been extensively studied for both black hole event horizon and the cosmological apparent horizon, mainly from two perspectives, on the one hand, by considering different proposals for the horizon entropy and analyzing the additional contributions required to satisfy the...
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Johan Casimiro (Pontificia Universidad Católica del Perú (PUCP))
The search for viable alternatives to Lambda-CDM requires not only new gravitational models, but also systematic criteria to identify which regions of their parameter space are physically meaningful and observationally testable. In this talk, I present a cosmological model based on non-metricity gravity (f(Q, Φ)), coupled to a non-canonical dilatonic scalar field, and discuss how dynamical...
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Rudranil Roy (Universidad de Tarapacá)
I will present a unified discrete quantum cosmological framework based on the Teleparallel Equivalent of General Relativity (TEGR). By formulating gravity strictly as a gauge theory of the non-compact translation group $T(4)$, we map the continuous Weitzenböck geometry onto a simplicial Regge lattice, where spacetime torsion manifests physically as localized structural dislocations quantified...
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Mr Carlos Mall
Non-commutative spacetime provides a framework for studying possible modifications of particle dynamics at high energy scales. In this work, we construct an eight-dimensional phase-space geometry, (Z^A=(x^\mu,p_\mu)), using the Snyder realization up to order (\ell^2). Starting from a flat phase-space metric, we obtain the induced metric and its inverse and derive the corresponding Levi-Civita...
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Francisco Plaza (Facultad de Ciencias Astronomicas y Geofisicas UNLP)
In this work, we propose an alternative model of cosmic inflation based on unimodular gravity (UG), an alternative theory of gravitation to General Relativity. The key feature of our model is that the primordial inhomogeneities are generated directly by the Higgs field. By combining the distinctive properties of unimodular gravity with the well-established characteristics of the Higgs field,...
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Pedro Rozín (CONICET - Instituto Balseiro)
This work focuses on the growth of cosmic structures within scale-dependent modified gravity frameworks, using the Hu-Sawicki model as a working example. In these scenarios, the effective gravitational coupling, Geff, depends on the scale. Consequently, the matter perturbation equation must be solved individually for every Fourier mode k, which inherently requires scale-dependent initial...
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Mr Francisco Barriga
In this work, we construct a three-dimensional non-relativistic Chern--Simons supergravity theory with both curvature and torsion within the Mielke--Baekler framework. We show that a consistent non-relativistic supergravity formulation requires starting from a N=2 supersymmetric extension of the Mielke--Baekler algebra and implementing a non-relativistic expansion via the semigroup expansion...
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11. Nonlinear Scalarization of Reissner-Nordström Black Holes in Scalar-Maxwell-Teleparallel GravityMr Joaquín Robledo
In this work, we investigate the scalarization of the Reissner-Nordström black hole within a scalar-tensor teleparallel gravity framework. This approach enables a direct comparison between scalarization mechanisms induced by a scalar field nonminimally coupled to the torsion scalar and those resulting from its coupling to the electromagnetic invariant. We demonstrate the existence of distinct...
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DAVID ALONSO LUZQUIÑOS SAAVEDRA (PUCP)
The adiabatic growth of a black hole embedded in a collisionless dark-matter halo can induce a substantial rearrangement of the surrounding phase-space distribution, leading to the formation of a steep central overdensity commonly referred to as a dark-matter spike. Such structures may enhance the dark-matter annihilation rate by several orders of magnitude and therefore constitute potentially...
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Mr Claudio Pérez
We revisit the asymptotic structure of the massless scalar field on four-dimensional Minkowski space, aiming to probe a broader class of field configurations and the conserved quantities they carry. To this end, we relax the standard asymptotic behaviour of the field by allowing polylogarithmic terms that decay at spatial infinity, extending the usual expansion beyond its leading fall-off....
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Mr Nitesh Kumar
Inflation provides a compelling framework for explaining the origin of primordial perturbations that seed the large-scale structure of the Universe. However, a consistent inflationary scenario must also account for the subsequent transition to a hot, radiation-dominated phase. In this work, we investigate the post-inflationary dynamics and reheating of Higgs-like inflation in scalar–torsion...
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Mr Eduardo Ubilluz
Cosmological inflation provides a mechanism to explain the origin of primordial fluctuations that give rise to anisotropies in the cosmic microwave background and the formation of large-scale structures in the Universe. In this work, we study primordial perturbations within the framework of modified teleparallel gravity $f(T,\phi,X)$, where $T$ is the torsion scalar, $\phi$ is a scalar field,...
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Miguel Angel Agama Flores (Universidad Nacional Mayor de San Marcos)
Inflationary attractor models yield robust predictions, but these may change when gravity is extended beyond general relativity. To investigate this, we study scalar perturbations in scalar--torsion theories described by $f(T,\phi)+P(\phi)X$. In flat gauge, we expand the action to second order, retaining the tetrad's scalar boost, whose variation imposes an additional constraint. Eliminating...
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Olaf Baake (Universidad Diego Portales)
Following Hartle and Thorne, we discuss slowly rotating stars using an expansion of the field equations in angular velocity while having the TOV equations of a non-rotating star as a background model. We use affine-null coordinates, which yield a particularly convenient multipole decoupling of the Einstein equations, allowing for writing down a master equation. Outside the star, the system...
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Andrés Burton Villalobos (Universidad de Tarapacá)
We formulate the phase-space stochastic inflationary dynamics in scalar-torsion $f(T,\phi)$ gravity. Applying cosmological perturbation theory (CPT) in the spatially flat gauge, we resolve the non-dynamical constraints, ensuring ghost-free stability with $P>0$ and luminal sound speed $c_s^2 = 1$, while deriving the anomalous effective mass $M_Q^2$ for non-linear models with $f_{,TT} \neq 0$....
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Mr Andrés Lueiza Colipí
We investigate a family of $k$-essence cosmological models selected by the requirement that the field equations admit nontrivial variational symmetry. For the $k$-essence theory with Lagrangian function $F(R,X,\phi)=f_{1}R+f_{2}(X,\phi)$ and $f_{2}(\phi,X)=\alpha X+\beta \exp\left((n-1)\phi\right)X^{n}$, the existence of the symmetry constrains the kinetic terms and introduces a conservation...
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Dr Susana J. Landau (Universidad de Buenos Aires)
In this talk, I will describe a novel estimator to quantify statistical tensions among multiple cosmological datasets simultaneously. This estimator generalizes the Difference-in-Means statistic, $Q_{\rm DM}$, to the multi-dataset regime. Our framework enables the detection of dominant tension directions in the shared parameter space. It further provides a geometric interpretation of the...
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Diego Miguel Navia Rojas (Universidad de Valparaíso)
The asymptotically flat plateau of tree-level Higgs inflation can sustain a transient ultra-slow-roll (USR) phase for specific pre-inflationary initial conditions. We systematically scan the phase space of initial field kinematics and identify trajectories where this non-attractor phase occurs near the horizon crossing of the largest observable CMB modes. Because USR violates the slow-roll...
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