Strength of gravity in asymptotic safe gravity

In summary, different theories of gravity, such as classical GR, LQG/LQC, and string/m theory, have different predictions for the strength of gravity in black holes. In classical GR, the strength of gravity increases to infinity as mass increases and distance decreases, resulting in a singularity at the center of a black hole. In LQG/LQC, the strength of gravity becomes repulsive near Planckian densities, leading to the prediction of a Planck star at the center of a black hole. In string/m theory, the strength of gravity results in a fuzz ball at Planckian densities. In asymptotic safe gravity theories, the strength of gravity tends to a finite fixed value as distance goes to 0, which
  • #1
kodama
978
132
in classical GR the strength of gravity increase to infinity as mass increases and distance decrease.

in classical GR a black hole consists of an event horizon, and a singularity of infinite density and point-size inside the black hole.

in LQG/LQC strength of gravity eventually becomes repulsive near Planckian densities leading to predictions of a Planck star at the center of a black hole

in string/m theory gravity results in a fuzz ball at Planckian densities

how does strength of gravity in asymptotic safe gravity behave as mass increases and distance decrease?

does it decrease then becomes repulsive at decreasing distance like color force in QCD which is also asymptotic safe ?

how does this affect predictions of black hole singularities ?

i.e if gravity behaves like gravity in asymptotic safe gravity, what is at the center of a black hole?
 
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  • #2
kodama said:
in classical GR the strength of gravity increase to infinity as mass increases and distance decrease.

in classical GR a black hole consists of an event horizon, and a singularity of infinite density and point-size inside the black hole.

in LQG/LQC strength of gravity eventually becomes repulsive near Planckian densities leading to predictions of a Planck star at the center of a black hole

in string/m theory gravity results in a fuzz ball at Planckian densities

how does strength of gravity in asymptotic safe gravity behave as mass increases and distance decrease?

In general, the term "asymptotic safety" means that interaction strength tends to a finite fixed value as distance goes to 0. Thus, a theory with any such finite value (positive, negative or zero) is asymptotically safe.

However, theories with zero strength are usually called "asymptotically free" (as it is a much nicer property). Normally, "asymptotically safe gravity" theories have a non-zero, usually positive, value.
 
  • #3
nikkkom said:
In general, the term "asymptotic safety" means that interaction strength tends to a finite fixed value as distance goes to 0. Thus, a theory with any such finite value (positive, negative or zero) is asymptotically safe.

However, theories with zero strength are usually called "asymptotically free" (as it is a much nicer property). Normally, "asymptotically safe gravity" theories have a non-zero, usually positive, value.

in LQC gravity goes to zero then becomes repulsive, is this also "asymptotic safety"

so in"asymptotically safe gravity" theories depending on that non-zero, usually positive, value, it's possible either black holes do not form from stellar collapse, or if they do form, something like a neutron star or quark star or new state of matter is inside the black hole, if gravity doesn't continue to grow stronger and isn't able to overcome pauli exclusion principle among fermions, instead of a singularity in classical GR
 

1. What is asymptotic safe gravity?

Asymptotic safe gravity is a theoretical framework that attempts to reconcile quantum mechanics and general relativity by proposing that gravity becomes weaker at shorter distances, rather than infinitely strong as predicted by traditional theories.

2. How is the strength of gravity in asymptotic safe gravity determined?

The strength of gravity in asymptotic safe gravity is determined by the fixed point of the renormalization group flow, which is the point at which the theory becomes self-consistent and no longer requires further corrections.

3. What implications does asymptotic safe gravity have for black holes?

Asymptotic safe gravity suggests that the singularity at the center of a black hole may not exist, and instead, there may be a smooth transition to a white hole on the other side. This has potential implications for the information paradox and the behavior of black holes in the early universe.

4. How does asymptotic safe gravity differ from other theories of quantum gravity?

Unlike other theories of quantum gravity, asymptotic safe gravity does not require the existence of extra dimensions or the introduction of new particles. It also does not rely on the concept of supersymmetry, which has yet to be experimentally verified.

5. What are the current challenges and limitations of asymptotic safe gravity?

One of the main challenges of asymptotic safe gravity is the lack of experimental evidence to support its predictions. Additionally, the theory has not yet been able to fully explain the observed expansion of the universe or the existence of dark matter. Further research and testing are needed to fully understand the potential of asymptotic safe gravity.

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