arXiv subjects

Gustavo Valdivia-Mera

Publications and source records attributed to Gustavo Valdivia-Mera.

7 recordsLinked to original sources

arXiv2026

Area-Information Trade-Offs in Acceleration Radiation from Atoms Falling into Black Holes

We develop a geometric theory of information processing in the Horizon-brightened acceleration radiation (HBAR) channel, in which the radiative horizon-area change provides an entropy budget for the information carried by the radiation field. Building on the quantum-optical description of atom--field interactions near the horizon and the resulting HBAR thermodynamic correspondence, we derive area-cost laws in the near-steady, thermally saturated regime. The accessible classical information and the mutual information generated between the radiation field and its environment are bounded by the associated radiative horizon-area budget. Reliability is incorporated through Fano's inequality, which translates a prescribed decoding error probability into an area requirement. We further derive Fisher-information speed limits that constrain the statistical evolution of the radiation field and place a lower bound on the duration required for correlation generation. Together, these results establish a bits-per-area principle linking black-hole thermodynamics, information geometry, and quantum information in the HBAR framework.

quant-ph↗

arXiv2026

The Helical SYK Model and Emergent Infrared Integrability

We construct a helical generalization of the Sachdev-Ye-Kitaev (SYK) model in $1+1$ dimensions, built from left- and right-moving Majorana fermions with local quartic interactions and random couplings in flavor-chirality space. These interactions organize into a symmetry-controlled hierarchy of quartic chirality sectors. At the most restrictive end of this hierarchy, symmetry forces the quartic structure into a density-density form, which admits an exact solution using bosonization, rendering the theory integrable. Once the full quartic helical interaction space is allowed, including purely chiral, chirality-balanced, and chirality-imbalanced sectors, this symmetry-protected integrable structure is lost. Nevertheless, the large-$N$ infrared limit remains analytically tractable through short-distance selection rules and disorder averaging. Using conformal perturbation theory about the free fixed point, we show that the entire interaction space is marginally irrelevant, and the theory thus becomes free and integrable in the IR.

hep-th↗

arXiv2025

Thermal nature of the causal diamond horizon: A hidden property of the inertial propagator

Inspired by the novel idea proposed by T.~Padmanabhan in \textit{Phys.\ Rev.\ D 100, 045024 (2019)}, we develop a method to uncover the hidden thermal properties of the inertial Feynman propagator in Minkowski spacetime in a causally consistent manner. This, in turn, enables a coherent interpretation based on future-directed propagation. In our approach, the Fourier transform is implemented following the convention used in the analysis of vacuum fluctuations. As a result, future-directed propagation across causal horizons can be consistently interpreted, from the perspective of an observer confined to a causally disconnected region, as the emission of scalar quanta at the past horizon and their absorption at the future horizon. Moreover, we find that the ratio between emission and absorption processes reproduces the characteristic Boltzmann factor of a thermal ensemble. We first apply this analysis to a causal diamond of length $2α$, performing a detailed study of the near-horizon geometry and thereby obtaining the temperature associated with the thermal behavior of the Minkowski vacuum as perceived by an observer with finite lifetime $2α$. For completeness, we also apply the method to the right Rindler wedge, recovering the well-known Unruh temperature, $T = a/(2π)$. Our results demonstrate that thermality can emerge directly from causal structure, independently of acceleration or gravity, with causal diamonds encoding intrinsic thermodynamic behavior in quantum field theory.

hep-th↗

arXiv2025

Horizon brightened acceleration radiation entropy in causal diamond geometry: A near-horizon perspective

In this article, we extend the horizon brightened acceleration radiation (HBAR) framework, originally introduced by Marlan Scully et al. in Proceedings of the National Academy of Sciences 115, 8131 (2018), to the causal diamond (CD) spacetime. We study a cloud of two-level atoms, injected at random times in the asymptotic past of the CD, freely falling toward its causal horizon and emitting scalar radiation via a weak dipole coupling to a quantum field. In the near-horizon region, an emergent conformal symmetry-captured by conformal quantum mechanics (CQM)-governs the field dynamics and allows analytic control of the emission process. We find that the radiation spectrum is thermal, with temperature $T_D = 1/(πα)$, and that the associated von Neumann entropy flux reproduces the entropy production of the radiation field. These results demonstrate that the causal horizons of the CD spacetime effectively act as a topological thermal reservoir, with thermal properties arising entirely from the global causal structure rather than from underlying microscopic degrees of freedom, highlighting that the validity of the HBAR framework is fundamentally tied to the existence of causal horizons, independent of the presence of a black hole.

hep-th↗

arXiv2025

On the Unruh effect and the thermofield double state

The purpose of this review is to provide a pedagogical development of the Unruh effect and the thermofield double state. In Section 2, we construct Rindler spacetime and analyze the perspective of an observer undergoing constant acceleration in Minkowski spacetime, which motivates the establishment of the relationship between the Fourier modes in both geometries using the Bogoliubov-Valatin transformation. In Section 3, we explore the underlying physics leading to the Unruh effect, its analogy with the thermal radiation observed around a Schwarzschild black hole, and its manifestation through the coupling of a particle detector to the scalar field. Finally, in Section 4, we derive the thermofield double state by conducting a Euclidean analysis of the field and geometry.

hep-th↗

arXiv2024

Path integral derivation of the thermofield double state in causal diamonds

In this article, we adopt the framework developed by R. Laflamme in \textit{Physica A}, \textbf{158}, pp. 58-63 (1989) to analyze the path integral of a massless -- conformally invariant -- scalar field defined on a causal diamond of size $2α$ in 1+1 dimensions. By examining the Euclidean geometry of the causal diamond, we establish that its structure is conformally related to the cylinder $S^{1}_β \otimes \mathbb{R}$, where the Euclidean time coordinate $τ$ has a periodicity of $β$. This property, along with the conformal symmetry of the fields, allows us to identify the connection between the thermofield double (TFD) state of causal diamonds and the Euclidean path integral defined on the two disconnected manifolds of the cylinder. Furthermore, we demonstrate that the temperature of the TFD state, derived from the conditions in the Euclidean geometry and analytically calculated, coincides with the temperature of the causal diamond known in the literature. This derivation highlights the universality of the connection between the Euclidean path integral formalism and the TFD state of the causal diamond, as well as it further establishes causal diamonds as a model that exhibits all desired properties of a system exhibiting the Unruh effect.

hep-th↗

arXiv2022

Anomalous changing of geodesics in hairy black holes

We study the motion of test particles and the propagation of light around neutral hairy black holes under the influence of a self-interacting real scalar field minimally coupled to gravity. The goal of the present work is to show that the time-like and null-like geodesics have an anomalous behaviour for a special range of parameters in the dense hair region, defined as $\sqrt{Ω(x_{h})}\leq r\leq 2MG_{N}/c^{2}$.

hep-th↗