Black hole in space time
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Black Holes in Space-Time: A Comprehensive Overview
Introduction to Black Holes in Space-Time
Black holes are regions in space-time where gravitational forces are so strong that nothing, not even light, can escape. They are solutions to Einstein's equations of general relativity and have been a subject of extensive research. This article synthesizes recent findings on black holes in various space-time dimensions, their formation, and their interaction with other cosmic phenomena.
Black Holes in Different Space-Time Dimensions
Three-Dimensional Space-Time Black Holes
In three-dimensional space-time, black holes can exist under the Einstein-Maxwell equations with a negative cosmological constant. These black holes are characterized by mass, angular momentum, and charge, similar to their four-dimensional counterparts. The entropy of these black holes is proportional to the perimeter length of the horizon, indicating a unique relationship between geometry and thermodynamics in lower dimensions1.
Higher-Dimensional Black Holes
Black holes in higher-dimensional space-times (N + 1 dimensions) exhibit properties that generalize the well-known Schwarzschild and Reissner-Nordstrom solutions. Notably, in dimensions N ≥ 5, black holes with a fixed mass can possess arbitrarily large angular momentum, a significant deviation from the four-dimensional case. These higher-dimensional black holes also include spinning solutions analogous to the Kerr metric2.
Quantum Effects and Black Hole Information Paradox
Virtual Black Holes and Quantum States
Quantum gravity introduces the concept of virtual black holes, which form statistical distributions of quantum states. Recent theories suggest that particles entering a black hole can generate firewalls, which can be replaced by 'footprints' in outgoing particles, preserving quantum information. This approach modifies the topology of the Schwarzschild metric, suggesting a radically different structure of space-time3.
Renormalization Group Improved Black Holes
Quantum gravitational effects can be studied by renormalizing the Schwarzschild metric, leading to a quantum spacetime that resembles the classical Reissner-Nordström black hole. This quantum spacetime can have multiple horizons depending on the mass and may form a cold, soliton-like remnant as it evaporates, potentially resolving the classical singularity at the core9.
Formation and Evolution of Black Holes
Nonsingular Black Holes
Nonsingular black holes describe a formation process from an initial vacuum region, transitioning through a static phase, and eventually evaporating back to a vacuum. These black holes are supported by finite density and pressures, behaving like a cosmological constant at small radii. The dynamic regions involve positive and negative energy fluxes, balancing the overall energy during collapse and evaporation4.
Cosmological Black Holes
In a cosmological context, black holes can form ab initio with the big bang singularity, expanding within the Einstein-de Sitter universe. These black holes exhibit unique properties such as increased perihelion precession and the absence of circular timelike orbits, differing significantly from isolated Schwarzschild black holes5.
Black Holes and Dark Matter
Interaction with Dark Matter Halos
Black holes can exist within dark matter halos, affecting their space-time metrics. The presence of dark matter increases the black hole horizon while shrinking the ergosphere. Interestingly, dark matter does not alter the singularity of black holes but creates a 'cusp' phenomenon observable at small scales, such as within the Milky Way8.
Novel Black Hole Spacetimes
Black-Bounce Spacetimes
Recent developments in black-bounce spacetimes propose regular black holes with non-zero area radii, leading to structures like traversable wormholes or bounces into future universes. These spacetimes maintain regularity and satisfy specific energy conditions, offering new insights into the causal structure and potential extremal cases of black holes10.
Conclusion
The study of black holes in various space-time dimensions, their quantum properties, and interactions with dark matter and cosmological phenomena continues to reveal the complex and fascinating nature of these cosmic entities. As research progresses, our understanding of black holes and their role in the universe will undoubtedly deepen, offering new perspectives on the fundamental laws of physics.
Sources and full results
Most relevant research papers on this topic
Black hole in three-dimensional spacetime.
The 2+1 black hole solution in 2+1 spacetime dimensions with a negative cosmological constant is similar to its 3+1 counterpart, with anti-de Sitter space appearing as a negative energy state separated by a mass gap from the continuous black hole spectrum.
Highly CitedBlack holes in higher dimensional space-times
Spinning black holes in higher dimensions can have arbitrarily large angular momentum, similar to Kerr and Schwarzschild metrics, but with a unique exception for N 5.
Highly CitedVirtual Black Holes and Space–Time Structure
Virtual black holes in quantum gravity can preserve quantum information and modify the structure of space-time, potentially radically changing our understanding of quantum gravity.
Formation and evaporation of nonsingular black holes.
Nonsingular black holes can form and evaporate, with their formation involving a compact space-time region of trapped surfaces and their evaporation involving negative-energy flux and surface pressure.
Highly CitedCosmological black holes: A black hole in the Einstein-de Sitter universe
The expanding black hole in the Einstein-de Sitter universe shows significant differences in timelike geodesics, with increased perihelion precession and the non-existence of circular timelike orbits.
Highly CitedThe spacetime in the neighborhood of a general isolated black hole
This paper constructs the spacetime in the vicinity of a general isolated black hole, using the weakly isolated horizon framework, and explores near-horizon geometry and its physical applications.
Parameterizations of black-hole spacetimes beyond circularity
This paper proposes a new parameterization for black-hole spacetimes that includes non-circular spacetimes, highlighting the need for regular black holes based on promoting the mass parameter to a function.
Black hole space-time in dark matter halo
The dark matter halo increases the black hole horizon but shrinks the ergosphere, but does not change the singularity of black holes, making the "cusp" phenomenon observable in the Milky Way.
Highly CitedRenormalization group improved black hole spacetimes
Quantum gravitational effects in black hole spacetimes can potentially remove the classical singularity at $r=0 or significantly milden it, potentially leading to a smooth de Sitter core.
Highly CitedNovel black-bounce spacetimes: Wormholes, regularity, energy conditions, and causal structure
Novel black-bounce spacetimes with non-zero area radius can lead to complex geometries and new theorems on static space-time regularity and classical energy conditions.
Highly Cited