# Understanding fields

1. Jul 7, 2012

### San K

Per the standard model, we currently have four kinds of interactions -
electromagnetic, weak, and strong nuclear interactions & gravity (?)

What are fields? How many of them are known?

For gravity, we need a mass to create a field and it does not pervade all of time-space (?)....i.e. it effects reduced with distance from the mass.
So mass is the source for creating the bend/gravity in time-space.

What about Higg's field? what is the source?

Moderator: I just realized, after posting, that this topic falls in particle physics as well.

2. Jul 7, 2012

### Simon Bridge

That would be correct - iirc there are several models that attempt to unify up to three of them. Unifying the lot of them is something of a holy grail.
Mathematical structures in field theory :) in the standard model, associated with a virtual particle
There is one for each fundamental interaction ... which would depend on the model in use. From above: four.
GR - gravity - has yet to be quantized ... which is one reason why the Higgs boson stuff is exciting people.
http://en.wikipedia.org/wiki/Quantum_field#Quantum_fields
That is an interesting question which the recent Higgs Boson work is hoping to help with. As it stands - yes, we understand gravity in terms of a classical field described by general relativity.
It is a mathematical construct within field theory which gives rise to the higgs boson and imparts mass to matter. The field itself is part of the nature of the Universe: the source is space-time itself... more accurately: it is a mathematical structure that we can use as a model in relation to space-time.
http://en.wikipedia.org/wiki/Higgs_field

See:

Last edited: Jul 7, 2012
3. Jul 7, 2012

### kloptok

The standard model describes three of the four forces, so all of them except gravity. Furthermore the electromagnetic and the weak interactions have been unified in a single framework, the electroweak interaction. Gravity has not been successfully quantized.

Electromagnetic fields you have surely heard of, as described by Maxwell's equations. A field is something which has a value at each point in spacetime. A vector field assigns a vector to each point, a scalar field assigns a scalar (i.e. a number) to each point. Quantum fields are what you get when you quantize a classical field, and the quanta of the fields are particles associated with that particular field. In the standard model each particle is associated with a field.

@Simon Bridge: Why do you talk about the Higgs as interesting for quantum gravity? As far as I know there is no such link, and this just creates confusion. If you know something about this please provide a source.

4. Jul 8, 2012

### Simon Bridge

You think it is less confusing to say that the particle responsible for mass has no link to gravity? You don't think that discovery of the Higgs boson has important consequences for the various approaches towards quantizing gravity? All those higgs-less methods are in trouble aren't they?

OK - the standard model does not have much to say about quantum gravity - the energy densities we have to work with are too small. I think this is the main area for misunderstanding - that you have to have mass to bend space-time. You need energy and lots of it ... the LHC is too puny to tell us anything directly about gravity. Doesn't mean it cannot tell us something indirectly - eg. http://vixra.org/pdf/1003.0202v1.pdf
... (loosly) attempts to reconcile the hierarchy problem with the Higgs mass by proposing a TeV scale quantum gravity.
Confirmation of the Higgs boson must, at the least, lend more weight to papers, like this one, that account for the Higgs mechanism in some way?

I don't mean to imply that the higgs boson is a quantum of gravity. But it is going to be important to theories of quantum gravity.

5. Jul 8, 2012

### Bill_K

I think the Higgs boson has nothing at all to do with quantum gravity except in the minds of a few crackpots. The paper you cited, as with all papers posted to viXra, has not been not peer-reviewed, and as such falls outside of the PF guidelines.

6. Jul 8, 2012

### kloptok

I think it is confusing to mix the Higgs with gravity, yes. The Higgs mechanism is a way of allowing massive fermions and weak gauge bosons without spoiling gauge invariance. It has no direct link to gravity as we describe it. For example ~99% of the proton mass is explained by other means than the Higgs. And actually I think it is misleading to say that the Higgs mechanism "explains" mass or that it is "responsible" for mass. Rather, it permits mass of weakly interacting particles. Where the coupling responsible for the mass value comes from is not given in the mechanism. Maybe quantum gravity can explain why elementary particles have the masses they do but I don't see how this connects do the Higgs mechanism. A discovery of the Higgs would be a triumph for the SM but not really for quantum gravity.

I don't see the relevance of higgsless models and if they are in trouble or not.

Laymen are obviously confused by this and many naively think that just because the Higgs mechanism has something to do with mass it must be intimately related to gravity. See e.g. these threads in the Particle Physics forum:

Well... it is not like that's the only paper that account for the Higgs mechanism in some way. The mechanism has been a part of the SM for many many years now and seen as the main alternative for giving mass to the W and the Z. And if you want to find a reference connecting the Higgs and quantum gravity, can you provide me with some paper that has been published in a peer-reviewed journal? That paper seems to have been cited one time only and is filled with speculations and conjectures.

7. Jul 8, 2012

### Simon Bridge

I agree - I disagree that it is less confusing to the layman to fail to mention any connection at all. I'll allow that I need to be more careful with my statements than I was ...
Fair enough ... I have seen viXra papers cited here before though - probably due to being accessible. A quick trawl produces:

Percacci P: The Higgs phenomenon in quantum gravity; Nuclear Physics B; Volume 353, Issue 1, 8 April 1991, Pages 271–290
http://dx.doi.org/10.1016/0550-3213(91)90510-5 [Broken]

El Naschie. M. L. Supersymmetry, transfinite neural networks, hyperbolic manifolds, quantumgravity and the Higgs; Chaos, Solitons & Fractals; Volume 22, Issue 5, December 2004, Pages 999–1006
http://dx.doi.org/10.1016/j.chaos.2004.03.030 [Broken]

Hasegawaa, K. et al. An attempt to solve the hierarchy problem based on gravity-gauge-Higgs unification scenario; Physics Letters B, Volume 604, Issues 1–2, 16 December 2004, Pages 133–143
http://dx.doi.org/10.1016/j.physletb.2004.10.038 [Broken]

Bezrukova, F. & Shaposhnikova, M. The Standard Model Higgs boson as the inflaton, Physics Letters B, Volume 659, Issue 3, 24 January 2008, Pages 703–706
http://dx.doi.org/10.1016/j.physletb.2007.11.072 [Broken]

Shaposhnikova, M. & Wetterichb, C. Asymptotic safety of gravity and the Higgs boson mass Physics Letters B, Volume 683, Issues 2–3, 18 January 2010, Pages 196–200
http://dx.doi.org/10.1016/j.physletb.2009.12.022 [Broken]

I'd rather have more recent ones...

Bezrukova, F. & Gorbunovd, D. S. Distinguishing between R2-inflation and Higgs-inflation; Physics Letters B, Volume 713, Issues 4–5, 18 July 2012, Pages 365–368
http://dx.doi.org/10.1016/j.physletb.2012.06.040 [Broken]
... but I thought inflation could not be the Higgs field?!

... anyway - perhaps there is a better way of describing all this activity which certainly appears to be trying to connect Higgs field with gravity in different ways.

Last edited by a moderator: May 6, 2017