Particles vs Fields: What's More Fundamental?

[petm1]

As far as I understand m theory, a string is a one-dimensional object. As to its size I once read that it was so small that it was able to wrap itself around a zero-dimensional elementary particle.

 

[Demystifier]

Yet another argument that particles are more fundamental than fields:
http://xxx.lanl.gov/abs/0705.3542

 

[CarlB]

Yet another argument that particles are more fundamental than fields:
http://xxx.lanl.gov/abs/0705.3542

Another elegant paper. When I read the abstract:

Practically measurable quantities resulting from quantum field theory are not described by hermitian operators, contradicting one of the cornerstone axioms of orthodox quantum theory. This could be a sign that some of the axioms of orthodox quantum theory should be reformulated. A nonorthodox reformulation of quantum theory based on integral curves of particle currents is advocated and possible measurable manifestations are discussed. The consistency with particle creation and destruction requires particles to be extended objects, which can be viewed as a new derivation of string theory. Within this reformulation, an indirect low-energy test of string theory is also possible.

I knew it had to discuss Bohmian mechanics and sure enough, it discusses the current algebra of Bohmian mechanics.

When one wants to unify gravitation and quantum mechanics, one naturally searches for a description of the two that is similar. This is a way of describing general relativity as a velocity vector field on a flat space. For the Schwarzschild and Kerr metric, this is well described in this paper:
http://www.arxiv.org/abs/gr-qc/0411060

By the way, if it has to be described by complicated mathematics, why is it called "elementary" particles? I think the reason complicated mathematics is used is because there's a lot more of that sort of mathematics available than elementary, so the first fit a drunk wanders upon will be a complicated one.

 

[Haelfix]

How about algebra of observables as the fundamental quantity, or rather nets of observables. All the fields and particles and so forth are just mathematical abstraction.

Of course, I don't actually believe that. =)

I feel the ultimate ontology has yet to be formulated precisely and in the meantime we are looking at incomplete asymptotics of the whole thing.

 

[rewebster]

In your opinion, what are more fundamental objects: particles or fields?

both




Of course, I have my own theory...


(just like almost everyone else here seems to have)

 

[Fra]

I can't vote either.

What is more important, the question or the matching answer? It seems they are unseparable. A question without at least a possible set of answers is as absurd as the other way around. They qualify each other. I sense particles and fields have a similary kind of relation, though not in any litteral sense.

/Fredrik

 

[humanino]

You have very well known physicists writing textbooks where they take one position or the other. Issuing a poll is funny. But this goes in GD, not physics. This thread is metaphysics.

I realize that moderators probably to not want to overload GD

 

[rewebster]

I don't know about anyone else, but when I see the 'term'/'label'--"metaphysics"---my first thought is "THE PARANORMAL"

I know its a broad based term, but...

 

[humanino]

when I see the 'term'/'label'--"metaphysics"---my first thought is "THE PARANORMAL"

Buy a dictionnary. You have vocabulary issues.

Definitions of metaphysics on the Web:

• the philosophical study of being and knowing
  wordnet.princeton.edu/perl/webwn[/URL]
  
  [*]Metaphysics (Greek words meta = after/beyond and physics = nature) is a branch of philosophy concerned with the study of "first principles" and "being" (ontology).
  [url=en.wikipedia.org/wiki/Metaphysics][B][color=blue][U]link to wiki[/U][/color][/B][/url]
  [/list][/quote]

 

[Fra]

> Buy a dictionnary. You have vocabulary issues.

He is not alone. With metaphysics I think "strings" I guess I need a dictionary too

/Fredrik

 

[humanino]

He is not alone. With metaphysics I think "strings" I guess I need a dictionary too

This really needs to go to GD. This is hilarious. You got me with this one

 

[meopemuk]

I vote for particles. I wrote a book, which argues that particles are more fundamental than fields. http://www.arxiv.org/physics/0504062 So, I have no other choice.

 

[birulami]

Well, since I was asked, I'll give an answer mostly undisturbed by real knowledge in the field (or fields:-) The more fundamental notion is the field. Assume everything is basically a field. When two fields interact --- and it has to be found out how this really happens --- both are transformed into one or more completely new fields. The location of interaction is more or less localized, subject to the Heisenberg uncertainty principle. Furthermore, the location of interaction is seemingly random in the case of a high number of interaction partners --- like a an electromagnetic wave hitting the screen behind the infamous two slits having lots of positions to chose from for interaction.

Cheers,
Harald.

 

[triggernum5]

Have you learned about huygen's principle? Its tough to explain without pics, but it attempts to explain EM propogation.. He said that light waves leaving a light source were the result of tiny wavelets, each radiating out from a point on the wave. I'm probably wrong, but I've always thought about photons to be the infinite set of points on the wavefront propagating the subsequent radiation..

 

[affinefield]

Yes to both questions.Schrodinger was the first to notice that quantum mechanical objects(everything)find their easiest and most natural representation in even NRQM as plain-wave solutions to a 2nd order PDE(a wave-equation),not as complicated little "spheres" held together in some fantastic way(like what Einstein was after via classical "geometrodynamics"as a means of getting rid of "singularities").It all goes back to finding a theory or description of matter which comprehends the results of the PARTICULAR EXPERIMENT/INTERACTION which quantum critters are capable of,...,a wave (electron diffraction),a particle(photoelectric effect).ANY theory which is capable of simultaneously comprehending BOTH of these possibilities is going to be "strange".

 

[affinefield]

Particles or Fields?.The origin,ultimately,of what you have in mind by the phrase "particle" is not just that which interacts via EM,Strong,Weak forces,but is also the seat or source of Gravitational/Inertial mass,the lower-case (m).This is not accounted for yet.It is still a brute fact,it is still "the right-hand-side of Einstein's field equations".Schrodinger,Dirac,ect.,were not out to account for the ultimate origin of inertial/gravitational mass with their original forms of the correct combination of particle-like and wave-like behaviors which depend upon the interactions observed.The "Matter/Force Problem" lives on.If you look at the 18 or so arbitrary parameters of the Standard Model,those numbers which come from experiment,and have to be put in "by hand" for the whole thing to work,it is,when I stop to think about it,amazing that the scheme works AT ALL!.I cannot REALLY "take-sides" in a debate over which is more "fundamental".Maybe particle/field is like space and time before Einstein,and we are just not asking the right questions,...,maybe.Who knows??

 

[affinefield]

I usually think in the following simple terms(analogy):Space and Time separate due to our scale,low-energy level,leads to the notion that "matter" and its "energy" are seperate.Spacetime-special relativity-removes the distinction,so there is no longer a separate "conservation-law" for matter and energy.Schrodinger,Dirac,Bohr,Born,Heisenberg,...,they come along and remove the distinction between "wavelike" and "particlelike",but they are forced to do so in a manner which is even more grossly removed from the realm of common sense than is the spacetime combination,and leads,eventually,to the quantum theory of fields,when,for example,Bohr and Rosenfield conclude that quantum mechanics cannot just be "right" for "matter" and NOT RIGHT for electromagnetic fields.They BOTH have to obey the rules for any consistent scheme describing their interaction.20th century physics is so magnificent,and we are still so amazingly ignorant,it is just wonderful.Any drastic attempt to describe EVERYTHING in terms of particles/or EVERYTHING in terms of fields contains within it the seeds of its own doom.The history of 20th century physics is littered with the attempts.

 

[affinefield]

I got the name Rosenfeld wrong yesterday.Bohr and Rosenfeld gave a profound analysis of the simultaneous measurability of the electric and magnetic field strengths,and basically concluded that,no matter how well you measure each of them,their values do not commute.This gave the "Copenhagen stamp-of-approval"to the work on quantizing the E-M field,which was already underway.Rosenfeld was also one of the first to seriously study the consequences of quantizing gravitation,and DeWitt,in his first of three papers on Quantum Gravity,from 1968(Physical Review),mentions this fact,...

 

[humanino]

I was serious when I was saying that this thread is not scientific, should not be here, and now I think it seriously challenges PF's quality. The best jokes are the shortest ones.

 

[affinefield]

I would like to correct a date:Bryce DeWitt's 3 famous quantum gravity papers were from 1967 not 1968,pardon me.

 

[affinefield]

Fritz Rohlich's "Classical Charged Particles" from 1965,Addison-Wesley,is always a good read.Hubert Goenner's "On The History of Unified Field Theories"at the Living Reviews in Relativity website will aprise the reader of some of the major schemes to get at "matter"(gravitational mass) and "electricity" geometrically.He takes the story to about 1933.I said the other day that I did not want to take sides,but I must."Fields",whether classical or quantum,are simply better understood than any notions we have ever had about "particles",so I must absolutely go with fields.

 

[affinefield]

Yeah,...,when Morse/Feshbach,way back in 1953,on the first page of chapter 1 of their "Methods of Theoretical Physics" said ",...,practically all of modern physics deals with fields,...,",they were not kidding.The bewildering variety of hadrons was only just beginning to become apparent.That was "the good old days",when starting from the full-blown Euler-Lagrange equations for the "meson-field" one might have hoped to actually get to decay-widths and cross-sections.Failure is the mother of moderation.No,the old "meat-and-potatoes" approach to the strong interactions was doomed(starting from the field equations themselves).Dispersion theory,S-Matrix and current-algebra were the compromises.

 

[lightgrav]

After a few months, the original question :
"what are more fundamental objects: particles or fields?"
[even leading the voters with OBJECTS ... tsk, tsk]
Demystifier resorted to :
"... another reason why particles could be more physical than fields..."

Certainly, fields are more generally useful ...
because they are not themselves observable/measurable,
we can ascribe pleasant features to them (e.g, conservation),
and those features will not immediately be shot down by experiment.

The trouble is finding nature's way of obtaining particle-like
measurables from the field ... is anybody doing solitons anymore?

 

[CarlB]

Well, I don't know if I count, but I certainly think I'm doing solitons.

The basic idea of solitons is that they are solutions to nonlinear equations. The simplest nonlinear equation is z^2 = z, which is the equation satisfied by density operator representations of particles. The solutions in the reals, 0 and 1, correspond to the cases where there is zero or one particle present. But to get useful physics out of it, you have to go to much more complicated fields.

But I don't think that this means that particles are more fundamental. The equation z^2 = z might just be a particle nonlinear approximation of a more fundamental nonlinear field equation.

 

[LostInSpaceTime]

In your opinion, what are more fundamental objects: particles or fields?
In other words, is QFT just a convenient mathematical way to calculate the properties of particles,
or
are particles just specific states of quantum fields?

Hey I'm new here on the boards just got kinda blindsided by particle physics one day about 6 months ago and let me say WOW! I love this stuff. ( This is a little intro to me, what I'm about and why I'm here. My answer to this post is below )You can't help but look to physics and math once you start thinking about life, where it came from, why it's here and so on; it just seems the next logical step. I must confess though my basic math skills are left to be desired. Trig I think gives me the most trouble and some parts of algebra. Once I got past the what the particles were like their names, how they reacted, how to read particle reactions, and I could mentally envision them(particles) everywhere, I bumped into the unfortunate problem of having to know more and more math the deeper into it I went. I've had gotten used to using their names and talked about them as if I was talking about cooking supper but when it came to those crazy equations I was( and still am) like holy @#$% how am I going to understand them? I knew they were supposed to read like detailed descriptions of interaction and such. I recognized some of the symbols but watching them interact on paper was puzzling to say the least. I'm 25 and I don't have a tremendous amount of time to dedicate to learning higher math(as I'm sure there are people that have started much sooner than I, and still have a long way to go) in any real time frame; so I set some minor goals and I'll see if I can obtain them. Right now I'm fishing around with this plasma physics stuff you know the whole "Electric Universe" and such? Big bang is a hoax and all that buzz. Kinda interesting but again I suppose I'm missing the best part not knowing the math. At the same time I'm using what I do know to read up on current events; can't wait for 2008 and that higgs boson. (maybe some thoughts on this from some?).
I really like the whole theology of physics as well. Right now I'm reading the Tao of physics; wonderful relations. Physics conversations are always so fun and thought provoking.

Anywho that's all I can think of to write about me for now if anyone has any questions comments just write back. Now to get to answer the question: In your opinion, what are more fundamental objects: particles or fields?

Lets see if I understand the question.
From what I understand all these fields you are talking about have particles to carry out their "deeds" ie: Light=Photon W+, W-,Z,e- and so on. So if these fields are made up of particles reacting with one another then it's the particles that make up the basics. But each of these particles have there own little force that reacts with the other ie: +,-, no charge, and fraction charges. These particles are the reactions we see, like how we see a magnet attract another mag, it's just little particles reacting with one another and their reactions are based on a pre-set charge, there seems to be a category of sub-forces to control them in turn to control us. I guess the question is not so much what is the fundamental objects but what came first the field or the particle?...or I could be crazy. That's why I'm here to ask question to people that are smarter than me so then I can become smarter than them.

 

[chroot]

I applaud for your interest in picking up physics as a hobby, LostInSpaceTime, but I have to warn you: the two books you've mentioned: The Big Bang Never Happened and The Tao of Physics are terrible, terrible books. They are effectively works of socially-acceptable crackpottery. I strongly advise you to steer clear of these kinds of books, and focus on reputable, mainstream works instead.

You might find some of the following books interesting:

The Particle Universe
The Feynman Lectures
A Tour of the Calculus

- Warren

 

[dreynaud]

Particle or field ?

One would be very prudent before giving any answer since the history of physics

Wave or point like object ? Cophenague interpretation says that they are complementary aspect of the reality (the particle).

The QFT generally gives rise to uncertainty relation between phase and number of particle (if I remember well, this was fisrt established by Bohr and Heisenberg (or Rosenfled) in the framwork of QFT; see also Feynman who explain this in his classical books).

The interpretation of this relation is the following : if you measure precisely the phase of a field, you can't measure simultaneously the number of particle of the field. Bohr's complementarity principle apply here. So that field aspect and particle aspect are two aspect of one thing : the "quantum field".

So I would vote a third propostion : "Quantum field".

(Note that a vote won't help : the scientific method doesn't incorporate such a method to invalidate a theory !).