arXiv subjects

Jiswin Varghese

Publications and source records attributed to Jiswin Varghese.

3 recordsLinked to original sources

arXiv2026

Quantum-Corrected Entropy Bounds on Black Hole Merger Efficiency

We examine the entropy balance of black hole mergers in the presence of quantum gravity corrections described by the Generalized Uncertainty Principle (GUP). Focusing on the coalescence of two non-spinning Schwarzschild black holes with unequal masses, we analyze the thermodynamic evolution from the initial binary system to the final merger remnant, explicitly accounting for energy loss through gravitational-wave emission. Using a logarithmically corrected entropy motivated by a quadratic GUP, we derive a generalized entropy change as a function of the gravitational-wave efficiency and the mass ratio of the merging components. The classical area theorem is recovered in the appropriate limit, while the GUP correction introduces a quantum-modified entropy bound that constrains the maximum allowed gravitational-wave energy emission. This bound is most restrictive for nearly equal-mass mergers, indicating an enhanced sensitivity of symmetric systems to quantum gravity effects.

gr-qc↗

arXiv2026

Detector Dependence of Inspiral Christodoulou Gravitational Wave Memory in Binary Black Hole Systems

The nonlinear gravitational-wave memory, or Christodoulou memory effect, is a permanent displacement produced by the self-interaction of gravitational waves predicted by General Relativity. In this work, we present GWMemoryLab, a modular numerical framework for investigating leading-order Christodoulou memory during the inspiral of non-spinning binary black hole systems within the post-Newtonian approximation. The framework implements modules for binary dynamics, post-Newtonian inspiral evolution, oscillatory waveform generation, gravitational-wave energy flux, and nonlinear memory accumulation. Analytical comparisons and convergence tests demonstrate numerical stability. We investigate the dependence of accumulated memory on binary mass ratio, total mass, and detector low-frequency cutoff. The simulations reveal an optimal total mass that maximizes the observable inspiral memory for a given detector bandwidth. Within the explored parameter space, the optimal mass follows an approximately inverse dependence on the detector low-frequency cutoff. This behaviour arises from the competition between increasing gravitational-wave luminosity and decreasing inspiral duration as the binary approaches the innermost stable circular orbit. These results provide insight into the detectability of nonlinear gravitational-wave memory and demonstrate the utility of GWMemoryLab for systematic parameter studies.

gr-qc↗

arXiv2026

Exact Analytical Phase Transitions, Horizon Bistability, and Thermodynamic State-Space Representation of Regular Hayward Black Holes

We establish exact analytical thresholds and present a unified thermodynamic state-space representation for the regular Hayward black hole, resolving the full phase structure without reliance on numerical approximations. By evaluating the Hawking temperature, Helmholtz free energy, and heat capacity against the classical Schwarzschild baseline, we derive the exact geometric watershed for the zero-temperature extremal remnant at $r_h = \sqrt3l$, along with the exact Davies critical transition at $r_h = 3l$. Within the intermediate regime $\sqrt{3}l < r_h < 3l$, we uncover a distinct horizon bistability where two distinct horizon radii share identical free energy and temperature profiles. We demonstrate that the Davies singularity acts as a precise thermodynamic divide, separating a locally stable ($C_V > 0$) quantum Small Black Hole branch from an unstable ($C_V < 0$) Large Black Hole branch. Furthermore, we evaluate the exact integrated non-area law entropy at the critical turning point, yielding $S_{turn} = πl^2 \left[ \frac{63}{8} + 2\ln(8l^2) \right]$. Finally, we introduce a compact, 3-parameter thermodynamic state-space diagnostic that tracks the continuous evolution of regular black holes from classical thermal evaporation to cold remnant lock, offering a quantitative framework for quantum-gravity phenomenology.

gr-qc↗