Search arXiv⌕ Search

arXiv subjects

Hishan Farfán-Bachiloglu

Publications and source records attributed to Hishan Farfán-Bachiloglu.

3 recordsLinked to original sources

Finite-range hair from a nonlocal matter sector: charged Yukawa black holes

{ We construct a new exact charged, static and spherically symmetric black-hole solution of the Einstein--Maxwell equations with an additional anisotropic matter sector, whose metric is the Reissner--Nordström geometry endowed with a Yukawa-type contribution. The Yukawa term is exponentially screened: it is visible in the strong-field region but carries no independent asymptotic charge. We obtain an analytic parametrization of the extremal curve, identify the condition for higher-order degenerate horizons, characterize the curvature singularity and establish the weak, null, dominant and strong energy conditions. We further study the horizon thermodynamics, including the conjugate variables associated with the amplitude and range of the Yukawa sector and the corresponding generalized Smarr relation. The photon sphere, shadow, ray-traced appearance and quasinormal ringdown are then analyzed, with quasinormal frequencies computed through the sixth-order WKB expansion and confirmed, overtones included, by an independent spectral method. {Confronting the model shadow with Event Horizon Telescope measurements of M87* and Sgr A* constrains the finite-range sector directly, favoring its strongly screened, near-Reissner--Nordström regime.} This provides a unified geometric and phenomenological characterization of finite-range charged black-hole hair in ordinary Einstein gravity. }

gr-qc↗

Phase-controlled quasi-bound states in the continuum and thermoelectric enhancement in Majorana-quantum-dot nanostructures

We investigate how the interplay between Majorana zero modes (MZMs) and bound states in the continuum (BICs) governs the electronic thermoelectric response of a crossbar-shaped quantum dot (QD) coupled to two topological-superconductor nanowires. Using the Green-function formalism, exact linear-response energy integrals, and their low-temperature Sommerfeld expansion, we analyze the spectral and thermoelectric properties of the system. We show that symmetry breaking converts BICs into quasi-BICs, allowing them to contribute to electrical and thermal transport and thereby generate a finite thermoelectric response. While unequal nanowire lengths, reflected in different intra-Majorana coupling strengths, produce only a modest enhancement of $ZT_{el}$, detuning the QD level increases $ZT_{el}$ by approximately one order of magnitude. Superconducting-phase control produces a much stronger enhancement, reaching $ZT_{el} \simeq 0.75$ through a quadratic transmission zero and a pronounced violation of the Wiedemann-Franz law. The low-temperature values $ZT^{max}_{el} \simeq 0.755$ and $\mathscr{L} /\mathscr{L}_{0} = 21/5$ are universal consequences of this quadratic antiresonance. Our results establish phase-tunable thermoelectric signatures of the Majorana-coupled interference structure and identify superconducting-phase control as an efficient means of engineering the electronic response of topological hybrid nanostructures.

cond-mat.mes-hall↗

Q-triplet characterization of atmospheric time series at Antofagasta: A missing values problem

Located in northern Chile (23.7°S, 70.4°W), Antofagasta has an exceptionally arid and stable climate characterized by minimal precipitation and consistent weather patterns. Nevertheless, despite these climate conditions being meaningful for several research and practical applications, our understanding of weather dynamics remains limited. The available meteorological data from 1969 to 2016 is analogical, which presents a significant challenge to analyze because these records are riddled with missing values, some measurements were taken at irregular measuring intervals, making it an interesting puzzle to grasp the Antofagasta's climate scenario. To overcome this issue, we present a comprehensive statistical analysis of atmospheric temperature, pressure, and humidity time series. Our analytical approach involves the q-triplet calculation method, serving as a powerful tool to identify distinctive behavior within systems under non-equilibrium states. Our results suggest that, in general, the q-triplet values satisfy the condition $q_\text{sens}<1<q_\text{stat}<q_\text{rel}$, a pattern that has been observed in previous studies.

physics.ao-ph↗