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Higher Dimensional Black Holes: Properties and Evolution
Properties of Higher Dimensional Non-Kerr Black Holes
Horizon and Ergosphere Characteristics
Higher dimensional (HD) black holes exhibit unique properties compared to their four-dimensional counterparts. In particular, the horizons and ergospheres of rotating HD deformed Kerr-like black holes are significantly influenced by the deformation parameter ( \epsilon ) and the number of spacetime dimensions ( D )1. The ergosphere, a region outside the event horizon where objects cannot remain in place, shows a much richer structure in HD black holes. This complexity enhances the efficiency of the Penrose process, a mechanism for energy extraction from a black hole, making it more effective than in four-dimensional Kerr black holes1.
Energy Extraction Efficiency
The Penrose process's efficiency in HD black holes is notably higher due to the sensitivity of the ergosphere size to both the deformation parameter and the extra dimensions. This increased efficiency suggests that HD black holes could potentially serve as more powerful energy sources compared to their four-dimensional counterparts1.
Evolution of Black Holes Using Hydrodynamic Analogy
Formation and Growth
The formation of black holes begins with the implosion of a star after it exhausts its nuclear fuel, leading to a critical mass-to-radius ratio that includes the Schwarzschild radius, a concept rooted in general relativity2. The evolution of black holes is further influenced by the behavior of HD gravitons, which, like light, cannot escape the black hole. This inability of HD gravitons to leave the black hole impacts its evolution, potentially altering the growth dynamics and the overall lifecycle of the black hole2.
Primordial Black Holes and Early Universe
Formation from Population III Stars
The first massive black holes likely formed from the collapse of Population III stars at redshifts ( z \geq 20 ). These early black holes evolved within the primordial gas surrounding them, undergoing complex dynamical, thermal, and chemical changes3. Simulations indicate that there was a significant delay, approximately ( 10^8 ) years, between the formation of these black holes and the onset of efficient accretion, a process crucial for the growth of supermassive black holes observed in the early universe3.
Accretion and Chemical Evolution
The mergers of relic H II regions with neighboring neutral minihaloes, containing high-density primordial gas, could facilitate the accretion onto Population III remnant black holes. However, the high optical depth to Lyman-Werner photons and the formation of H2 molecules within these regions create a bottleneck for early black hole growth. Additionally, the formation of deuterium hydride (HD) molecules could enable the formation of Population 11.5 stars, further influencing the structure formation in the early universe3.
Conclusion
Higher dimensional black holes present a fascinating area of study with their unique properties and enhanced energy extraction capabilities. The evolution of these black holes, influenced by HD gravitons and primordial conditions, provides critical insights into the early universe's structure formation and the growth of supermassive black holes. Understanding these processes not only enriches our knowledge of black hole physics but also sheds light on the fundamental mechanisms driving cosmic evolution.
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Most relevant research papers on this topic
Higher dimensional non-Kerr black hole and energy extraction
Higher dimensional non-Kerr black holes have a richer ergosphere structure, making the Penrose process more efficient for energy extraction compared to four-dimensional Kerr black holes.
A Possible Evolution of Black Holes by Using a Hydrodynamic Analogy
The inability of HD-gravitons to leave black holes significantly affects their evolution, as it is impossible for light to leave the black hole.
The aftermath of the first stars: massive black holes
The first massive black holes formed by Population III stars at redshifts z20 may have faced a crucial early bottleneck, requiring more massive seed black holes for efficient accretion.
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