SearcharxivSearch

arXiv · 1312.7501

Variational Results and Solutions in Gauge Gravity and a Bifurcation Analysis of Black Hole Orbital Dynamics

Abstract

An analysis of all known spherically symmetric solutions to the field equations originating from the Riemann tensor quadratic curvature Lagrangian is presented. A new exact solution is found for the field equation originating from the "energy-momentum" equation of the gauge gravity theory. Imposing equivalence between the Palatini and standard variational field equations yields an algebraic condition that restricts the number spacetime solutions to gauge gravity. An analysis of a new spherically symmetric solution to the conformal gravity field equations is also presented. Point particle orbital dynamics in both the Schwarzschild and Reissner-Nordstrom black hole spacetimes are analyzed as 2-d conservative bifurcation phenomena. The Schwarzschild dynamics exhibit both saddle-center and transcritical bifurcation points and a calculation of periastron precession is presented that incorporates a phase-plane analysis of the relativistic equations of motion. Level curves of constant energy are illustrated for both timelike and null geodesics and a phase-plane analysis of dynamical invariance between the proper and coordinate time reference frames is discussed. The Reissner-Nordstrom dynamics exhibit saddle-center, transcritical, pseudo-transcritical, and additional bifurcations that combine all three previous bifurcations in various combinations. Periastron precession in the Reissner-Nordstrom spacetime is analyzed using the phase-plane and bifurcation techniques and extended to include a bifurcation point of the dynamics. A numerical solution at these parameter values illustrates that such orbits typically yield a much larger precession value compared to the standard value for timelike, precession. The acausal geodesics considered by Brigman are also discussed and their precession value is calculated.

Explore related subjects

Keep this discovery

BibTeXRIS

Bruce Herold Dean. 2013-12-29. Variational Results and Solutions in Gauge Gravity and a Bifurcation Analysis of Black Hole Orbital Dynamics. https://arxiv.org/abs/1312.7501

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related papers

Electrovacuum Black Hole Uniqueness

We prove the black hole uniqueness conjecture in the axially symmetric, stationary, electrovacuum setting, subject to the refined asymptotic analysis of the associated singular harmonic maps, which includes an analyticity hypothesis at the axes. More precisely, it is shown that any asymptotically flat solution of the Einstein--Maxwell equations in this class, with more than one black hole horizon component is either: Majumdar--Papapetrou, up to a duality rotation, in which case all logarithmic angle defects vanish, or every finite axis rod logarithmic angle defect is strictly negative and hence every interaction force is strictly attractive. The proof extends the singular harmonic map method used for vacuum Kerr uniqueness in [18].

gr-qc

Constraining Modified Mass-to-Horizon Cosmology Through Primordial Inflationary Observables

We investigate slow-roll inflation in a modified cosmological framework inspired by a generalized mass-to-horizon relation (MHR), $M=\gamma {c^2 L^n}/{G}$, where $n$ is a real parameter and $\gamma$ a dimensional constant. Using Padmanabhan's emergence paradigm, we derive the modified Friedmann equations for a flat FRW universe and analyze the dynamics of a canonical scalar field (inflaton) under the slow-roll approximation. We study the resulting inflationary phenomenology for power-law and Starobinsky potentials. For power-law potentials, the MHR modification fails to reconcile these models with current CMB constraints on $r$ and $n_s$. In contrast, Starobinsky inflation exhibits significant sensitivity to deviations from $n=1$. A perturbative analysis ($n=1+\Delta$) yields corrections to inflationary observables. We observe that the scalar power-spectrum normalization, under a fixed-Starobinsky prescription, imposes the stringent constraint $0.960 \lesssim n \lesssim 1.040$ for $N=60$ efolds. This is considerably tighter than spectral-index bounds. Our results establish inflation, particularly Starobinsky-like models, as a sensitive probe of generalized horizon thermodynamics and departures from standard MHR scaling.

gr-qc

Improving the Sensitivity of Gravitational Wave Detection with Weighted Conformal Prediction

In the last decade, kilometre-scale interferometric gravitational-wave detectors have observed hundreds of compact binary mergers, the majority of which are binary black holes. However, the data are noise-dominated, and multiple independent search algorithms (pipelines) are used to enhance sensitivity and improve robustness. Rather than the standard approach of selecting the most significant pipeline output, we combine the outputs from all pipelines using a conformal prediction-based framework to provide statistically rigorous confidence estimates for candidate events. While combining pipelines improves sensitivity and ranking robustness, it requires a principled statistical framework that remains valid as data properties evolve across observing runs. A key challenge is distribution shifts between simulated datasets used for training and calibration and the real, unlabelled, observations used for testing, which can invalidate coverage guarantees and bias confidence estimates. In this work, we address this challenge by incorporating likelihood-ratio reweighting into our conformal prediction framework to account for covariate shift. Using mock datasets containing simulated signals, we demonstrate that weighted conformal prediction restores well-calibrated coverage under covariate shift and increases the confidence of events near the detection threshold, recovering true signals that would otherwise be missed.

gr-qc