Does any field, other than gravity, bend space-time?

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Discussion Overview

The discussion centers around whether any fields, aside from gravity, can bend or interact with space-time. It explores theoretical frameworks such as general relativity and quantum field theory, and considers implications for concepts like dark energy and the Higgs field.

Discussion Character

  • Exploratory
  • Debate/contested
  • Technical explanation
  • Conceptual clarification

Main Points Raised

  • Some participants suggest that all energy, and thus all fields, can bend space-time, as described in general relativity.
  • Others argue that gravity is not a field but rather the structure of space-time itself, complicating the relationship between gravity and quantum field theories.
  • One participant mentions that elements of the stress-energy tensor interact with space-time, including momentum and potentially dark energy due to its negative pressure.
  • There is a discussion about the Higgs field and whether it interacts with space-time.
  • Some participants highlight a fundamental conflict between general relativity and quantum mechanics regarding the nature of space-time, with GR requiring a dynamic structure and QM relying on a fixed background.
  • A later reply introduces candidate theories for quantum gravity that may address the conflict between GR and QM, such as loop quantum gravity and ideas from string theory.
  • Participants express differing views on whether the relationship between particles and space-time is one of mutual change or if one influences the other more significantly.

Areas of Agreement / Disagreement

Participants do not reach a consensus; multiple competing views remain regarding the interaction of fields with space-time and the relationship between general relativity and quantum mechanics.

Contextual Notes

There are unresolved theoretical issues regarding the nature of quantum gravity and its effects on space-time, as well as the implications of different theoretical frameworks on the understanding of gravity.

San K
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In particle physics, quantum field theories such as the Standard Model describe nature in terms of fields. Each field has a complementary description as the set of particles of a particular type.

Does any field, other than gravity, bend (or have any noticeable interaction with) space-time?
 
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If you want to describe gravity with general relativity, gravity is not a field - it is the structure of spacetime itself. All energy bends spacetime, so all fields can do this.
If you want to describe gravity with quantum field theory (neglecting the theoretical issues here), it acts like a field, not like bent spacetime.
 
mfb said:
If you want to describe gravity with general relativity, gravity is not a field - it is the structure of spacetime itself. All energy bends spacetime, so all fields can do this.
If you want to describe gravity with quantum field theory (neglecting the theoretical issues here), it acts like a field, not like bent spacetime.

good answer and interesting info. thanks mfb
 
Anything in the Stress Energy Tensor interacts with spacetime...including momentum.
And I presume dark energy since it has a negative pressure and pressure is also a component of the SET.

Do any of the Higgs fields interact??
 
If you want to describe gravity with quantum field theory (neglecting the theoretical issues here), it acts like a field, not like bent spacetime.
Lacking a theory, it is hard to say how strong quantum gravity acts. It may do something much worse to spacetime than just bend it!
 
Bill's post brings to mind a fundamental conflict between GR and QM: I believe no one has yet figured out how to resolve that on one hand GR requires a dynamic spacetime while QM relies on a fixed, non dynamic spacetime structure. One simple way to picture this conflict is that, as you know, elements of the stress energy tensor in GR is the source of spacetime curvature; in QM, the fixed geometric spacetime background, as say in string theory, imparts the vibrational characteristics of particles. Change the spacetime background in string theory and you change the vibrational modes and that means particle characteristics change.

That's a major reason we can't fit GR/gravity into the Standard Model of particle physics.
 
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Good posts Bill K and Naty1.

Interesting...GR Vs QM...another example of the long standing differing perspectives...in attempting to describe the same reality

someday we will be able to clearly see both perspectives and reconcile them like we now do between Classical/Newtonian Physics and GR.

Is the particle/gravity changing time-space or is space-time changing the particle?
or are they both changing each other?_________________________________________________________________
QM says to GR --- "listen its just a bend (in space-time), not the end"...:approve:
 
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mfb said:
If you want to describe gravity with general relativity, gravity is not a field - it is the structure of spacetime itself. All energy bends spacetime, so all fields can do this.
If you want to describe gravity with quantum field theory (neglecting the theoretical issues here), it acts like a field, not like bent spacetime.

Hmmm, isn't the metric in GR a tensor field? You take derivatives of it to get the connection and curvature tensors. Aren't they tensor fields as well?
 
...in attempting to describe the same reality

maybe the same, maybe not...I keep an open mind

I think about it as being analogously related to distance versus close up view:
At a mile distant, a house looks tiny; up close, not so much.

Which 'view' is accurate...which is 'reality' ?

Then add that the distant view is delayed more than the close view due to the finite speed of light...Then add spacetime curvature and that distant view provides only an apparent position [like gravitational lensing]. Then assume a velocity...then an acceleration...everything begins to change even more...as in length contraction,time dilation, and Unruh type temperature and particle differences...
 
  • #10
Naty1 said:
maybe the same, maybe not...I keep an open mind

I think about it as being analogously related to distance versus close up view:
At a mile distant, a house looks tiny; up close, not so much.

ya Naty1 or analogously to two observers in separate frames of references with different accelerations/velocities and their view of ordering of events

Naty1 said:
Which 'view' is accurate...which is 'reality' ?

Then add that the distant view is delayed more than the close view due to the finite speed of light...Then add spacetime curvature and that distant view provides only an apparent position [like gravitational lensing]. Then assume a velocity...then an acceleration...everything begins to change even more...as in length contraction,time dilation, and Unruh type temperature and particle differences...

however, fortunately, in GR we are able to reconcile (the differences in viewpoints between) these frames of references accurately, and completely, via the logic/calculations

but we are not able to fully understand/reconcile fields between GR/QM perspectives, yet
 
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  • #11
Bill_K said:
Lacking a theory [of quantum gravity], it is hard to say how strong quantum gravity acts.


Naty1 said:
Bill's post brings to mind a fundamental conflict between GR and QM: I believe no one has yet figured out how to resolve that on one hand GR requires a dynamic spacetime while QM relies on a fixed, non dynamic spacetime structure.

That's a major reason we can't fit GR/gravity into the Standard Model of particle physics.
Yes, it is true that we have no fully developed and established theory of quantum gravity. But I don't agree that there is still a fundamental conflict which we can't resolve. We have a couple of candidate theories which provide strong hints how this "fundamental conflict" can be resolved and that it already has been done - at least partially. QG theories addressing background independence (I am aware of) are loop quantum gravity, asymptotic safety and some formulations of string theory (especially ideas from gauge/gravity duality). I bet there are more ...
 

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