Related Experiment Video
Updated: Jan 6, 2026
07:46
Setting Limits on Supersymmetry Using Simplified Models
Published on: November 15, 2013
8.9K
Superradiant Axionic Black-Hole Clouds as Seeds for Graviton Squeezing
Panagiotis Dorlis1, N E Mavromatos1,2, Sarben Sarkar2
1National Technical University of Athens, Physics Division, School of Applied Mathematical and Physical Sciences, Zografou Campus, Athens 157 80, Greece.
Physical Review Letters
|October 25, 2025
Summary
Standard general relativity (GR) and Chern-Simons (CS) gravity can produce entangled gravitons interacting with axionic clouds around black holes. GR
Area of Science:
- Theoretical physics
- Gravitational physics
- Quantum field theory
Background:
- Kerr black holes possess superradiant instabilities that can amplify perturbations.
- Axionic clouds can form around black holes, interacting with spacetime and particles.
- Gravitational waves are ripples in spacetime, and their quantum nature involves gravitons.
Purpose of the Study:
- To investigate the production of entangled gravitons via interactions between axionic clouds and black hole backgrounds.
- To compare the graviton production mechanisms in standard general relativity (GR) and Chern-Simons (CS) gravity.
- To estimate the squeezing effect of graviton production and discuss observational implications.
Main Methods:
- Analytical calculations in the nonrelativistic limit for superradiance.
- Modeling graviton production from axion annihilation and decay processes.
- Comparing theoretical predictions with existing LIGO data and future detection prospects.
Main Results:
- Both GR and CS gravity can generate multi-mode squeezed states of entangled gravitons.
- The GR-induced squeezing effect from axion annihilation significantly dominates over the CS-induced effect.
- Long-lived axionic clouds lead to substantial squeezing, with implications for current and future gravitational wave observations.
Conclusions:
- The study provides a theoretical framework for understanding entangled graviton production around black holes.
- Results offer a new method for constraining axion properties and black hole environments using gravitational wave data.
- This work opens avenues for future searches for exotic gravitational phenomena with advanced detectors.
Related Concept Videos
01:10Detection of Black Holes
2.5K
Although black holes were theoretically postulated in the 1920s, they remained outside the domain of observational astronomy until the 1970s.
Their closest cousins are neutron stars, which are composed almost entirely of neutrons packed against each other, making them extremely dense. A neutron star has the same mass as the Sun but its diameter is only a few kilometers. Therefore, the escape velocity from their surface is close to the speed of light.
Not until the 1960s, when the first neutron...
Their closest cousins are neutron stars, which are composed almost entirely of neutrons packed against each other, making them extremely dense. A neutron star has the same mass as the Sun but its diameter is only a few kilometers. Therefore, the escape velocity from their surface is close to the speed of light.
Not until the 1960s, when the first neutron...
2.5K
01:14Gravitation Between Spherically Symmetric Masses
1.3K
The gravitational potential energy between two spherically symmetric bodies can be calculated from the masses and the distance between the bodies, assuming that the center of mass is concentrated at the respective centers of the bodies.
1.3K
01:21Schwarzschild Radius and Event Horizon
2.6K
No object with a finite mass can travel faster than the speed of light in a vacuum. This fact has an interesting consequence in the domain of extremely high gravitational fields.
The minimum speed required to launch a projectile from the surface of an object to which it is gravitationally bound so that it eventually escapes the object’s gravitational field is called the escape velocity. The escape velocity is independent of the mass of the object. Merging the idea of escape...
The minimum speed required to launch a projectile from the surface of an object to which it is gravitationally bound so that it eventually escapes the object’s gravitational field is called the escape velocity. The escape velocity is independent of the mass of the object. Merging the idea of escape...
2.6K
01:17The Principle of Superposition and the Gravitational Field
2.0K
The principle of superposition applies to gravitational forces of objects that are sufficiently far apart. It states that the net gravitational force on a point object is the vector sum of the gravitational forces on it due to various objects. The principle helps calculate the force by listing the individual forces and then vectorially summing them up. However, it should be noted that the principle of superposition is not always apparent. In the presence of a second force, the first force could...
2.0K
01:27Gravity between Spherical Bodies
9.3K
Newton's law of gravitation describes the gravitational force between any two point masses. However, for extended spherical objects like the Earth, the Moon, and other planets, the law holds with an assumption that masses of spherical objects are concentrated at their respective centers.
This assumption can be proved easily by showing that the expression for gravitational potential energy between a hollow sphere of mass (M) and a point mass (m) is the same as it would be for a pair of extended...
This assumption can be proved easily by showing that the expression for gravitational potential energy between a hollow sphere of mass (M) and a point mass (m) is the same as it would be for a pair of extended...
9.3K
01:20Momentum And Radiation Pressure
2.4K
An object absorbing an electromagnetic wave would experience a force in the direction of propagation of the wave. This force occurs because electromagnetic waves contain and transport momentum. The force accounts for the wave's radiation pressure exerted on the object. Maxwell's prediction was confirmed in 1903 by Nichols and Hull by precisely measuring radiation pressures with a torsion balance. The measuring instrument had mirrors suspended from a fiber kept inside a glass container.
2.4K