Causality Aspects of Modified Kerr-Newman spacetimes

Abstract

In this paper, we address the problem of causality violation in the solutions of Einstein equations and seek possible causality restoration mechanisms in modifed theories of gravity. We choose for the above problem, the causality violation due to the existence of closed time-like curves in the context of Kerr-Newman black hole. We first revisit and quantify the details of the causality violation in the Kerr-Newman spacetime. We then show that the issue is also existent in two of the modified solutions to the Kerr Newman spacetime: The Non-Commutativity inspired solution and the f(R)-Gravity modifed solution. We explore the possibility of mechanisms present within the model that prevent causality violation. We show that, in both the models, the model parameters can be chosen such that the causality violating region is eliminated. We argue that in the context of non commutativity inspired solution, the non commutativity parameter can be chosen such that the causality violating region is eliminated and the inner horizon is no longer the Cauchy horizon. We then discuss the geodesic connectivity of the causality violating region in both the scenarios and quantify the geodesics that have points in the causality violating regions. We also discuss the causal aspects of Kerr Newman deSitter/antideSitter spacetimes.

arXiv comment17 pages, 18 figures

References in corpus (26)

• Observation of Gravitational Waves from a Binary Black Hole Merger
• Planck 2015 results. XIII. Cosmological parameters
• Noncommutative geometry inspired Schwarzschild black hole
• Rotating regular black holes
• Quasinormal modes and Strong Cosmic Censorship
• Noncommutative geometry inspired charged black holes
• Recent developments in gravitational collapse and spacetime singularities
• Regular black hole metrics and the weak energy condition
• Non-commutative geometry inspired higher-dimensional charged, black holes
• Charged rotating noncommutative black holes
• Gedanken Experiments to Destroy a Black Hole II: Kerr-Newman Black Holes Cannot be Over-Charged or Over-Spun
• Energy conditions and their cosmological implications
• Regular rotating black holes and the weak energy condition
• A model of radiating black hole in noncommutative geometry
• Classical collapse to black holes and quantum bounces: A review
• A black hole mass threshold from non-singular quantum gravitational collapse
• A model for non-singular black hole collapse and evaporation
• Regular black holes and energy conditions
• Charged particle motion in Kerr-Newmann space-times
• Quantum Field Theory in Spaces with Closed Time-Like Curves
• A non-singular black hole model as a possible end-product of gravitational collapse
• Gravitational collapse to a Kerr-Newman black hole
• Ringholes and closed timelike curves
• Detailed study of geodesics in the Kerr-Newman-(A)dS spactime and the rotating charged black hole spacetime in $f(R)$ gravity
• On the behavior of causal geodesics on a Kerr-de Sitter spacetime
• Unwrapping Closed Timelike Curves

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