arXiv subjects

A. Baruah

Publications and source records attributed to A. Baruah.

3 recordsLinked to original sources

arXiv2026

Connecting Neutrino Masses, Dark Matter and Leptogenesis from $\Delta(54)$ Flavor with Triple Inverse Seesaw

In this present study, an extended Delta 54 flavor symmetry model incorporating two standard model Higgs doublets is investigated. This model generates neutrino masses through the triple inverse seesaw mechanism. It predicts deviations from tribimaximal mixing, yielding a nonzero reactor angle and an atmospheric mixing angle in the upper octant. In addition, the CP-violating phase and the Jarlskog invariant are found to be consistent with current neutrino oscillation data. Our study also includes the dark matter sector by evaluating the relic abundance and active neutrino dark matter mixing under relevant cosmological constraints. Furthermore, baryogenesis is achieved through resonant leptogenesis at the TeV scale including flavor effects. We obtain the observed baryon asymmetry, for right-handed neutrino mass 10 TeV and mass splitting d.

hep-ph↗

arXiv2025

Infrared Extended Uncertainty Principle Corrections and Quintessence-Induced Topology of Reissner-Nordstr\"om AdS Black Holes

We present a unified topological and geometric analysis of charged Anti-de Sitter (AdS) black holes immersed in a quintessence field, incorporating infrared gravitational corrections arising from the Extended Uncertainty Principle (EUP). The latter modifies the standard Heisenberg uncertainty relation by introducing a minimal momentum/maximal length scale, which effectively captures long-wavelength quantum gravitational effects relevant to black hole thermodynamics in curved spacetimes. We derive analytic expressions for the corrected Hawking temperature, entropy and heat capacity in terms of the EUP deformation parameter. Furthermore, the inclusion of quintessence, characterized by barotropic indices $\omega_q = -\frac{2}{3}$ and $\omega_q = -\frac{1}{3}$, modifies the black hole metric function. By studying the relaxation-time function $\tau(r_h)$, we identify a number of inflection points that depends sensitively on the equation of state parameter of quintessence, indicating a nontrivial impact of the latter on the black hole phase structure. Applying Duan's topological current method to the off-shell free energy, we compute integer-valued winding numbers associated with each thermodynamic critical point. A parallel topological analysis of the photon sphere assigns charges $ \pm 1 $ to individual light rings, showing that quintessence effects can trigger the splitting or merging of photon spheres, while preserving the total exterior topological charge of $-1$.

gr-qc↗

arXiv2025

Kalb-Ramond Black Holes Sourced by ModMax Electrodynamics: Some Perturbative Properties in the Phantom Sector

We formulate and analyze a new class of electrically charged black hole (BH) solutions in Lorentz-violating gravity, where nonlinear ModMax electrodynamics is nonminimally coupled to a Kalb-Ramond (KR) two-form field. The spontaneous breaking of local Lorentz symmetry is triggered by a nonzero vacuum expectation value of the KR field, characterized by a small dimensionless parameter $\ell$. To incorporate both standard and phantom sectors, we introduce a discrete sign-flip parameter $\zeta = \pm1$, which flips the gauge-kinetic terms in the phantom ($\zeta = -1$) branch. Assuming a vanishing cosmological constant and a self-interacting potential with minimum $V' = 0$, we obtain exact analytical solutions for the metric function and electric potential. The resulting spacetime interpolates between Schwarzschild, Reissner-Nordstrom, and ModMax BHs, with curvature scalars showing deviations controlled by $(\ell, \gamma, \zeta)$. We study scalar, electromagnetic, and gravitational perturbations using both frequency-domain (Pade-averaged WKB) and time-domain (Gundlach-Price-Pullin plus Prony) methods. We find that increasing either $\ell$ or the ModMax parameter $\gamma$ enhances the real and imaginary parts of QNMs, indicating higher oscillation frequencies and faster damping, especially in the phantom sector. The effective potentials deepen under phantom deformation, supporting more tightly bound modes. Furthermore, we analyze the greybody factors and compute the sparsity $\eta$ of Hawking radiation, which quantifies the nonthermal character of particle emission. We show that $\eta$ is significantly affected by $\ell$, decreasing with increasing Lorentz violation and asymptotically approaching a scaled version of the Schwarzschild value.

gr-qc↗