Higher-derivative Lorentz-breaking dispersion relations: a thermal description

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This work explores various manifestations of bumblebee gravity within the metric--affine formalism. We investigate the impact of the Lorentz violation parameter, denoted as $X$, on the modification of the \textit{Hawking} temperature. Our calculations reveal that as $X$ increases, the values of the \textit{Hawking} temperature attenuate. To examine the behavior of massless scalar perturbations, specifically the \textit{quasinormal} modes, we employ the WKB method. The transmission and reflection coefficients are determined through our calculations. The outcomes indicate that a stronger Lorentz--violating parameter results in slower damping oscillations of gravitational waves. To comprehend the influence of the \textit{quasinormal} spectrum on time--dependent scattering phenomena, we present a detailed analysis of scalar perturbations in the time--domain solution. Additionally, we conduct an investigation on shadows, revealing that larger values of $X$ correspond to larger shadow radii. Furthermore, we constrain the magnitude of the shadow radii using the EHT horizon--scale image of $Sgr A^*$. Finally, we calculate both the time delay and the deflection angle.

Section: The General Setup and Hawking Temperaturementioning

confidence: 99%

Gravitational traces of bumblebee gravity in metric–affine formalism

Araújo Filho,

Hassanabadi,

Heidari

et al. 2024

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“…This remarks are only possible due to existence of exotic matter. Furthermore, it is worth highlighting that the thermodynamic aspects have been extensively studied in various contexts, including cosmological scenarios [40,[136][137][138][139][140][141][142][143][144][145][146][147][148][149] and other related areas [150][151][152][153][154][155]. Finally, in order to provide a general overview of our results, we compare them with the Schwarzschild case in table 3.…”

Section: Schwarzschildmentioning

confidence: 99%

Analysis of a regular black hole in Verlinde’s gravity

Araújo Filho

2023

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This work focuses on the examination of a regular black hole within Verlinde’s emergent gravity, specifically investigating the Hayward-like (modified) solution. The study reveals the existence of three horizons under certain conditions, i.e. an event horizon and two Cauchy horizons. Our results indicate regions which phase transitions occur based on the analysis of heat capacity and Hawking temperature. To compute the latter quantity, we utilize three distinct methods: the surface gravity approach, Hawking radiation, and the application of the first law of thermodynamics. In the case of the latter approach, it is imperative to introduce a correction to ensure the preservation of the Bekenstein–Hawking area law. Geodesic trajectories and critical orbits (photon spheres) are calculated, highlighting the presence of three light rings. Additionally, we investigate the black hole shadows. Furthermore, the quasinormal modes are explored using third- and sixth-order Wentzel–Kramers–Brillouin approximations. In particular, we observe stable and unstable oscillations for certain frequencies. Finally, in order to comprehend the phenomena of time-dependent scattering in this scenario, we provide an investigation of the time-domain solution.

“…Based exclusively on the modified dispersion relations (MDRs), the investigation of many facets of a given theory may be undertaken [31], including its thermal behavior. In the literature, there exists a variety of recent works involving the thermodynamic properties in many different contexts, namely, Lorentz violation [32][33][34][35][36][37][38][39][40][41][42], bouncing Universe [43], loop quantum gravity [44], Einstein-aether theory [45], graviton [46], five-dimensional Chern-Simons theory [47] and others [48][49][50][51]. Nevertheless, from a MDR, there does not exist up to now a thermal study of massive particles in the Ellis wormhole scenario.…”

Section: Introductionmentioning

confidence: 99%

Thermodynamical properties of an ideal gas in a traversable wormhole

Araújo Filho,

Furtado,

Reis

et al. 2023

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In this work, we analyze the thermodynamic properties of non--interacting particles under influence of the gravitational field of a traversable wormhole. In particular, we investigate how the thermodynamic quantities are affected by the Ellis wormhole geometry, considering three different regions to our study: asymptotically far, close to the throat, and at the throat. The thermodynamic quantities turn out to depend strongly on parameter that controls the wormhole throat radius. By varying it, there exist an expressive modification in the thermodynamic state quantities, exhibiting both usual matter and dark energy--like behaviors. Finally, the interactions are regarded to the energy density and it seem to indicate that it ``cures" the dark energy--like features.