What's the smallest black hole
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The Smallest Black Hole: Insights from Recent Research
Introduction to Small Black Holes
Black holes are regions in space where the gravitational pull is so strong that not even light can escape. While most people are familiar with stellar-mass black holes and supermassive black holes, recent research has delved into the existence and characteristics of much smaller black holes. These small black holes, often referred to as primordial black holes or quantum black holes, offer unique insights into the early universe and fundamental physics.
Primordial Black Holes: Formation and Characteristics
Primordial black holes (PBHs) are hypothesized to have formed during the chaotic conditions of the early universe, shortly after the Big Bang. These black holes could have masses significantly smaller than stellar black holes, potentially down to (10^{-5}) grams7 9. The formation of these black holes is attributed to density fluctuations in the early universe, which could have led to regions of space collapsing under their own gravity9.
Quantum Black Holes: The Smallest and Heaviest Particles
Quantum black holes are considered the smallest conceivable black holes, with microscopic sizes but macroscopic masses. These black holes are theorized to be the heaviest elementary particles and could play a role in explaining ultra-high energy cosmic rays detected on Earth3. Additionally, quantum black holes might contribute to dark matter, providing a potential solution to one of cosmology's biggest mysteries3.
Observational Challenges and Methods
Detecting small black holes, whether primordial or quantum, poses significant challenges. Their small size and mass make them difficult to observe directly. However, researchers have proposed various methods to detect or set upper limits on their abundance. For instance, the effects of evaporated particles from PBHs on big bang nucleosynthesis, the cosmic microwave background, and cosmic ray backgrounds provide indirect evidence of their existence9. Additionally, gravitational lensing and dynamical effects offer potential observational signatures of these elusive objects9.
Smallest Supermassive Black Holes
While the focus is often on the smallest black holes in terms of mass, researchers are also interested in the smallest supermassive black holes. These black holes, with masses ranging from (10^4) to (10^6) solar masses, provide crucial insights into the formation and evolution of massive black holes in the universe2. Studying these black holes helps us understand the interactions between black holes and galaxies, as well as the growth of black holes from primordial seeds2.
Theoretical Models and Simulations
Theoretical models and simulations play a crucial role in understanding small black holes. For example, a matrix model consisting of (2 \times 2) traceless hermitian matrices has been used as a toy model to study black hole dynamics. This model exhibits chaos and a transition to integrability, providing insights into the behavior of black holes under different conditions1. Additionally, supersymmetric higher-derivative interactions in supergravity have been proposed to encapsulate finite size corrections to the microscopic entropy of small black holes, allowing for precise counting of their microstates5.
Conclusion
The study of the smallest black holes, whether primordial, quantum, or the smallest supermassive black holes, offers valuable insights into the early universe, fundamental physics, and the nature of black holes. While direct observation remains challenging, theoretical models, simulations, and indirect observational methods continue to advance our understanding of these enigmatic objects. As research progresses, we may uncover more about the role these small black holes play in the cosmos and their potential contributions to dark matter and cosmic structure.
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Most relevant research papers on this topic
Smallest matrix black hole model in the classical limit
The smallest matrix black hole model can transition from chaos to integrability when a parameter related to an $SO(2)$ angular momentum is tuned to a critical value.
The Smallest Supermassive Black Holes
Small supermassive black holes with masses of 10-4-10-6 M sun offer valuable insights into primordial seed black hole populations and their interactions with galaxies, but their discovery is challenging.
Are Black Holes Elementary Particles
Quantum black holes are the smallest and heaviest elementary particles, potentially resolving cosmic ray paradoxes and playing a role as dark matter in cosmology.
The Smallest Black Hole
The smallest black hole is a macroscopic object, with its horizon being its surface, and it can communicate with the rest of the universe through the sphere of radius R.
PreprintPrecision Counting of Small Black Holes
This study tests the hypothesis that supersymmetric higher-derivative interactions in = 2 supergravity can accurately probe black-hole micro-states, potentially revealing new insights into string theory.
Highly CitedAbsorption Cross-Section of Small Black Holes
The absorption cross-section of small nonrotating black holes is 1/8 of the cross-section of massive scalar particles, with the latter being exactly 1/8 of the former for all energies in the limit where the wavelength is larger than the Schwarzschild radius.
Highly CitedObservational Signatures of High-Redshift Quasars and Local Relics of Black Hole Seeds
High-redshift quasars show rapid growth of billion-solar-mass black holes, while low redshift dwarf galaxies reveal the mass of black hole seeds, crucial for understanding their origin in the universe.
Cosmological effects of primordial black holes
Small black holes, formed from density fluctuations in the early universe, may provide valuable information on early universe conditions.
Highly CitedConstraints on primordial black holes
Primordial black holes may play an important cosmological role and provide a unique probe of the early Universe, even if they contribute only a small amount of dark matter.
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