arXiv subjects

S. D. Pathak

Publications and source records attributed to S. D. Pathak.

14 recordsLinked to original sources

arXiv2026

Photon angular momentum near Planck scale

We study the angular momentum structure of the gauge field in Lorentz covariant relativistic generalized uncertainty principle (RGUP) framework incorporating Planck scale minimal length effects. Using Noether's theorem for higher derivative RGUP-modified gauge field Lagrangian, we obtain the canonical and symmetric (Belinfante) energy-momentum tensors and the corresponding gauge spin and orbital angular momentum currents. We show that the canonical and Belinfante-Rosenfeld angular-momentum tensors continue to satisfy the standard conservation law in the presence of Planck-scale corrections. %These results support the stability of fundamental conservation laws under high-energy modifications. The RGUP corrections introduce higher-order contributions to the angular momentum density and momentum flow, yielding a modified Poynting vector, with the Maxwell limit recovered for vanishing RGUP parameter.

hep-ph↗

arXiv2025

Inflation Driven by Scalar-Neutrino Coupling in a Mass-Varying Neutrino Framework

We propose a cosmological framework in which neutrino masses evolve dynamically through coupling with a scalar field that simultaneously drives inflation. The neutrino mass is modeled as a power-law, exponential, or hybrid function of the scalar field, yielding an effective potential that includes neutrino backreaction. Starting from the Einstein-Hilbert action in a flat FLRW background, we derive the modified Friedmann and Klein Gordon equations incorporating this coupling. Using the Fermi-Dirac integrals, we account for the continuous transition of neutrinos from relativistic to non-relativistic regimes. The inflationary dynamics are analyzed via the slow roll parameters derived from the effective potential. Our results show that the scalar neutrino coupling alters the potential slope and curvature, thereby influencing the duration of inflation. The hybrid coupling form provides the most flexible realization, unifying neutrino mass generation with early universe inflation within a single scalar field framework.

astro-ph.CO↗

arXiv2025

Unified Framework for Geodesic Dynamics with Conservative, Dissipative, and GUP Effects

We derive generalized geodesic equations in curved spacetime that include conservative forces, dissipative effects, and quantum-gravity-motivated minimal-length corrections. Conservative interactions are incorporated through external vector potentials, while dissipative dynamics arise from an exponential rescaling of the particle Lagrangian. Phenomenological study of Quantum-gravity effects is introduced via Generalized Uncertainty Principle (GUP) deformed Poisson brackets in the Hamiltonian framework. We show that free-particle geodesics remain unaffected at leading order, but external potentials induce velocity-dependent corrections, implying possible violations of the equivalence principle. As an application, we analyze modified trajectories in Friedmann-Lemaitre-Robertson-Walker (FLRW) universes dominated by dust, radiation, stiff matter, and dark energy. Our results establish a unified approach to conservative, dissipative, and GUP-corrected geodesics, providing a framework to probe the interplay between external forces, spacetime curvature, and Planck-scale physics.

gr-qc↗

arXiv2025

Stark Energy Shifts due to Quantum Gravity in RGUP Algebra

In this paper, we investigate the Stark effect in the hydrogen atom under an external electric field, incorporating relativistic generalized uncertainty principle (RGUP) corrections within Minkowskian spacetime and calculate the upper bound on $\beta$ the RGUP parameter. Employing RGUP algebra and the Stetsko-Tkachuk approximation, we derive modifications to the energy spectrum for degenerate and non-degenerate states. The perturbed Hamiltonian, modified by RGUP, enfold quantum gravitational effects. Our results reveal quantum gravitational corrections to the Stark energy spectrum in the relativistic regime, with energy shifts for non-degenerate ($n=1$) and degenerate ($n \neq 1$) cases showing additional terms proportional to $\beta$. These findings reduce to standard Stark effect results and non-relativistic GUP frameworks in the limits $\beta\rightarrow 0$ and $c \rightarrow \infty $, establishing our model as a generalized framework for analyzing minimal length effects in relativistic quantum systems.

gr-qc↗

arXiv2025

RGUP Corrections to Scalar and Fermionic Fields

We investigate the Relativistic Generalized Uncertainty Principle (RGUP) effects on scalar and fermionic fields using the Stetsko-Tkachuk approximation. Modified equations of motion, Hamiltonians, and stress-energy tensors are derived in Minkowski spacetime, incorporating quantum gravitational corrections that ensure a minimal observable length and revert to standard dynamics when corrections are absent. For fermionic fields in curved spacetime, spin connections maintain gravitational consistency. This framework, applicable to high-energy physics, black hole thermodynamics, and cosmology, integrates quantum gravity into relativistic field theories.

gr-qc↗

arXiv2024

Deformed algebraic structure of angular momenta: GUP perspective

The prediction of a minimal length scale by various quantum gravity candidates (such as string/M theory, Doubly Special Relativity, Loop Quantum Gravity and others) have suggested modification of Heisenberg Uncertainty Principle (HUP), resulting in the Generalized Uncertainty Principle (GUP). In this short review, we investigate the origins of the GUP and examine higher-order models, focusing on the linear plus quadratic form of the GUP. We extend the concept of minimal length to minimal angular resolution, which plays a crucial role in modifying angular momentum and its associated algebra. A comparison is made between the standard angular momentum commutator algebra and that modified by the GUP. Finally, we review its application in the hydrogen atom spectra and and discuss future endeavors.

gr-qc↗

arXiv2024

Generalized Uncertainty Principle and the Zeeman Effect: Relativistic Corrections Unveiled

In this paper, we calculate the relativistic corrections to the Zeeman effect for hydrogen-like atoms based on the Generalized Uncertainty Principle (GUP). We propose a relativistic GUP algebra using the Stetsko and Tkachuk approximation and incorporate these corrections into the Zeeman effect. In the relativistic limit, our results recover previously derived GUP corrections as well as the standard Lande energy shift expression when GUP effects are absent. This work presents a generalized expression that accounts for both relativistic and GUP corrections to the Zeeman effect.

quant-ph↗

arXiv2024

Quantum Gravity Corrections to Hawking Radiation via GUP

In this paper we explore the effects of a Generalized Uncertainty Principle (GUP) on Schwarzschild black hole. In particular, we incorporate the effects of GUP into the Parikh-Wilczek tunneling process for Hawking radiation. To this effect, we observe that results obtained due to GUP correction resemble that of the Reissner-Nordstr\"{om} black hole, showing similarities to the nature of an electric charge. We also find that, within this framework, the emission is not purely thermal, thus addressing the information loss problem through the correlation function.

gr-qc↗

arXiv2024

Inflection Point of Minimally Coupled Tachyonic Scalar Field

In this paper, we investigate the behaviour of a minimally coupled tachyonic scalar field at inflection points in an accelerating universe. We consider the different expansion factors and obtain potentials of tachyonic scalar field. Inflection points of homogeneous tachyonic scalar field is calculated for these potentials. We employ the tools of dynamical system analysis for the considered potentials and obtain the stable points.

gr-qc↗

arXiv2024

Generalized uncertainty principle distorted quintessence dynamics

In this paper, we invoke a generalized uncertainty principle (GUP) in the symmetry-reduced cosmological Hamiltonian for a universe driven by a quintessence scalar field with potential. Our study focuses on semi-classical regime. In particular, we derive the GUP-distorted Friedmann, Raychaudhuri, and the Klein-Gordon equation. This is followed by a systematic analysis of the qualitative dynamics for the choice of potential $V(\phi)= V_0 \sinh^{-n}{(\mu \phi)}$. This involves constructing an autonomous dynamical system of equations by choosing appropriate dynamical variables, followed by a qualitative study using linear stability theory. Our analysis shows that incorporating GUP significantly changes the existing fixed points compared to the limiting case without quantum effects by switching off the GUP.

gr-qc↗

arXiv2024

Quantum deformed phantom dynamics in light of the generalized uncertainty principle

Quantum gravity has been baffling the theoretical physicist for decades now: both for its mathematical obscurity and phenomenological testing. Nevertheless, the new era of precision cosmology presents a promising avenue to test the effects of quantum gravity. In this study, we consider a bottom-up approach. Without resorting to any candidate quantum gravity, we invoke a generalized uncertainty principle (GUP) directly into the cosmological Hamiltonian for a universe sourced by a phantom scalar field with potential to study the early epoch of the evolution. This is followed by a systematic analysis of the dynamics, both qualitatively and quantitatively. Our qualitative analysis shows that the introduction of GUP significantly alters the existence of fixed points for the potential considered in this contribution. In addition, we confirm the existence of an inflationary epoch and analyze the behavior of relevant cosmological parameters with respect to the strength of GUP distortion.

gr-qc↗

arXiv2017

Dynamics of coupled phantom and tachyon fields

In this paper, we apply the dynamical analysis to a coupled phantom field with scaling potential taking particular forms of the coupling (linear and combination of linear), and present phase space analysis. We investigate if there exist late time accelerated scaling attractor that has the ratio of dark energy and dark matter densities of the order one. We observe that the scrutinized couplings cannot alleviate the coincidence problem, however acquire stable late time accelerated solutions. We also discuss coupled tachyon field with inverse square potential assuming linear coupling.

gr-qc↗

arXiv2016

Thermodynamics of interacting tachyonic scalar field

In this paper we discuss the laws of thermodynamics for interacting tachyonic scalar field. The components of the tachyonic scalar field in the universe are taken to exist in the state of non-equilibrium initially, but due to interaction they undergo a transition towards the equilibrium state. We show that the zeroth law of thermodynamics demands interaction among the components of cosmic field. The second law of thermodynamics is governing dynamics in transfer of energy among the three components of the proposed field with local violation of conservation of energy for individual components.

gr-qc↗

arXiv2015

Dynamics of interacting quintessence

In this paper, we investigate coupled quintessence with scaling potential assuming specific forms of the coupling as $A$ namely, $α\dot{ρ_m}$, $β\dot{ρ_ϕ}$ and $σ(\dot{ρ_m}+\dot{ρ_ϕ})$, and present phase space analysis for three different interacting models. We focus on the attractor solutions that can give rise to late time acceleration with $Ω_{DE}/Ω_{DM}$ of order unity in order to alleviate the coincidence problem.

gr-qc↗