Can We Unify Quantum Gravity with the Other Fundamental Forces?

  • Thread starter Thread starter AmiBlackwelder
  • Start date Start date
  • Tags Tags
    Gravity
AI Thread Summary
The discussion centers on the challenges of unifying quantum gravity with the other fundamental forces, highlighting that while superstring theory is a leading candidate, no definitive theory currently exists. Participants express confusion about the relationship between gravity and quantum mechanics, questioning whether gravity disappears at quantum scales and if quantum gravity is inherently linked to gravity itself. It is noted that gravity operates on both large and small scales, unlike the other three forces, which primarily affect smaller particles. The conversation emphasizes the need for a quantum field theory approach to describe gravity similarly to how other forces are treated, but acknowledges the complexities involved. Overall, the quest for a unified theory of quantum gravity remains an active area of research with many unanswered questions.
AmiBlackwelder
Messages
9
Reaction score
0
Do we have any theories to unify quantum gravity to gravity?
What is the opinion on this?

What about gravity to the other 3 forces?
 
Physics news on Phys.org
Gravity disappears?

Is it true when we apply quantum mechanics to gravity, it disappears and so does space?


Does this mean quantum gravity disappears too?

If so, does this imply quantum gravity and gravity are linked? possibly to be unified?
 
AmiBlackwelder said:
Do we have any theories to unify quantum gravity to gravity?
What is the opinion on this?

What about gravity to the other 3 forces?

The main option that attempts to unify gravity with the other fundamental forces is superstring theory.

The fundamental forces with the exception of gravity, were unified under the standard model of particle physics.

A theory of quantum gravity would describe gravity, so no unification of the theories would be required.
 
Last edited:
Where did you get this idea from?

It is most certainly false.
 
So quantum gravity exists because natural gravity as most know it exists?

So, if gravity disappeared quantum gravity would too?
 
From Lawrence Krauss's book
 
Or more accurately one of his lectures.
 
AmiBlackwelder said:
So quantum gravity exists because natural gravity as most know it exists?

So, if gravity disappeared quantum gravity would too?

The term 'quantum gravity' refers to a theory that describes both the standard model of particle physics (that's where the word quantum comes from) and gravity. It's not a separate force.

At the moment we don't have a working theory of quantum gravity. It's still being researched.

Gravity isn't going to disappear but if it did then the research on quantum gravity would surely stop because we'd have bigger problems to worry about!
 
LOL,

I don't think it is any time soon, LOL

I'm just wondering theoretically what this all means.

So, when we hear 'quantum gravity' what is meant is the standard model plus gravity.

But, I'm confused, because how do we know that the gravity that pushes on the big stuff is the same gravity working on the small stuff?

And does it push that too?
 
  • #10
AmiBlackwelder said:
LOL,

I don't think it is any time soon, LOL

I'm just wondering theoretically what this all means.

So, when we hear 'quantum gravity' what is meant is the standard model plus gravity.

But, I'm confused, because how do we know that the gravity that pushes on the big stuff is the same gravity working on the small stuff?

And does it push that too?

The force due to gravity has always been measured to be proportional to mass and the mass of an object is the sum of the masses of its parts.

The effect of gravity has been measured on individual particles so we have no reason to doubt it.

We don't know what happens when gravity becomes very very weak. It's believed to be quantised and that's where it gets tricky.
 
Last edited:
  • #11
Ok, so gravity then works on the big and small.

But the other three forces seem to work on only the small, that seems weird. And gravity also seems to affect light and be a property of space itself? curvature?

the other three forces are not like this?
 
  • #12
Oh, also- the virtual particles follow quantum laws right? I've heard that. Just double checking.

So, does this mean, quantum laws...the same as the natural laws?

And is it fair to say these natural laws are just our description of what particles are doing and not necessarily an absolute in and of itself? Meaning the particles behaved and so we see this behavior and call it laws...not that these laws were first and made the particles act this way?
 
  • #13
AmiBlackwelder said:
Ok, so gravity then works on the big and small.

But the other three forces seem to work on only the small, that seems weird. And gravity also seems to affect light and be a property of space itself? curvature?

the other three forces are not like this?

All forces work on the big and the small. Just take all the forces on the smaller parts of a bigger object and add them up.

Our best theory of gravity describes it as a space-time curvature. The other forces are usually just treated as acting in space and time.
 
  • #14
AmiBlackwelder said:
Do we have any theories to unify quantum gravity to gravity?
What is the opinion on this?

What about gravity to the other 3 forces?

There need to be some clarification here.

There is something called quantum field theory (QFT). Within this formulation, we have successfully described the electromagnetic interaction, the weak interaction, and the strong interaction. So as is natural with human tendency, we think, hey, since gravity is a "force" as well, there should be a way to describe it using QFT as well.

So that, naively, is what is meant as trying to find a quantum picture of gravity. It is trying to describe it in the analogous way as QFT. Whether we will be successful or not is a different matter.

Zz.
 
  • Like
Likes 1 person
  • #15
He is almost certainly speaking poetically.
Which lecture?
 
  • #16
I think that she is thinking of the breakdown of general relativity when applied to things on a quantum level.
 
  • #17
Two different threads have been merged because they are both based on the same topic by the same OP.

Zz.
 
  • #18
AmiBlackwelder said:
From Lawrence Krauss's book

AmiBlackwelder said:
Or more accurately one of his lectures.

In this forum, we require a more extensive and detailed source than that. So you might as well learn about it now. If you cite a book, please write down the author, title, and page number exactly. If you cite a lecture online, provide the exact URL and where approximately is this particular source.

This forum, while it may be an open, public forum, has a stricter quality control. However, it also gives you an idea on how scientists operate and communicate, whereby one of the things we do is we justify what we say with appropriate and clear sources, if this isn't something standard and well-known. Thus, we try to instill the same philosophy and practice among the members participating in the physics discussion here.

Zz.
 
  • Like
Likes 1 person
  • #19
I'm looking for the source, thanks. Just trying to clear up misinformation from books and online so I can understand all this.
 

Similar threads

I How did the theory of quantum gravity begin?
Replies
16
Views
2K
B Is Time a Fundamental Force in Physics?
Replies
15
Views
4K
B Why are we trying to unify all the physical forces?
Replies
2
Views
9K
I Unifying string theory and loop quantum gravity
Replies
2
Views
3K
I Why there's No Unified Theory ?
Replies
3
Views
1K
A Looking for the earliest articles about Quantum Gravity
Replies
2
Views
2K
B Questions about the Universe: Positive & negative fields and effects
Replies
4
Views
4K
B Can I have $5 Million for my Knowledge
Replies
1
Views
1K
I Is Gravity a Force or Curvature?
Replies
20
Views
4K
I What Explains the Odd Behavior of the Four Fundamental Forces?
Replies
13
Views
2K

Hot Threads

Recent Insights

Back
Top