String Theory & Elementary Particles: What's Real?

[Jupiter60]

TL;DR

String theory and elementary particles.

If string theory is correct does it mean that elementary particles like photons, electrons, and quarks don't really exist or does it mean they do but are made of cosmic strings and so therefore are not elementary?

 

[Vanadium 50]

does it mean that elementary particles like photons, electrons, and quarks don't really exist

Of course not.

does it mean they do but are made of cosmic strings

String theory has nothing to do with cosmic strings.

 

[Jupiter60]

If string theory is true, does it mean quarks, electrons, photons etc. are made of strings and so are not really elementary particles, but are made of strings?

 

[Jupiter60]

I have done some reading and can see indeed that cosmic strings and the string in string theory are different entities. Cosmic strings can exist without string theory.

 

[Vanadium 50]

If string theory is true, does it mean quarks, electrons, photons etc. are made of strings and so are not really elementary particles, but are made of strings?

Are you going to ask the same question over and over again, ignoring the replies? Then what is the point in replying?

 

[Jupiter60]

Are you going to ask the same question over and over again, ignoring the replies? Then what is the point in replying?

I'm not asking about cosmic strings in the second question, but the string in string theory. Apparently the two are different entities, not the same thing. I got them mixed up.

 

[Vanadium 50]

Asked and answered

does it mean that elementary particles like photons, electrons, and quarks don't really exist

Of course not.

 

[Demystifier]

If string theory is true, does it mean quarks, electrons, photons etc. are made of strings and so are not really elementary particles, but are made of strings?

Yes, that's true.

 

[McFisch]

The idea behind string theory is that elementary particles are just excitations of strings. You probably came across that old guitar-analogy already: Strings are like the strings on a guitar and the different modes of vibration - what we call the notes - are what we see as the elementary particles. In that sense it would be wrong to say that quarks, electrons, etc. are "made" of strings.

As to whether particles exist and are fundamental: While string theory is still in its infancy, one might anyway say that particles are not elementary but the underlying quantum fields are (Quantum Field Theory is already well established and experimentally verified). For example the Photon is just a local excitation of the electro-magnetic field. So is the Photon or the field elementary? It's a matter of definition. The term "exist" is even more vague. Do notes exist? In some "effecitve" way, of course. Particles are something with certain properties that we can measure.

Sorry, can't say anything about cosmic strings as I hardly know anything about them.

 

[aurorahigh]

Summary:: String theory and elementary particles.

If string theory is correct does it mean that elementary particles like photons, electrons, and quarks don't really exist or does it mean they do but are made of cosmic strings and so therefore are not elementary?

i believe string theory and field theory are combined.this allows for particles and the fields to exist in the same
unified theory.of course this u.f.t.has not been proven yet.

 

[arivero]

The idea behind string theory is that elementary particles are just excitations of strings. You probably came across that old guitar-analogy already: Strings are like the strings on a guitar and the different modes of vibration - what we call the notes - are what we see as the elementary particles. In that sense it would be wrong to say that quarks, electrons, etc. are "made" of strings.

Is it a good analogy? quarks and leptons are the fundamental level of the tower of states, so it is not about different modes of vibrations but different ways for attaching the string to the resonance box.

 

[ChrisVer]

I don't think physics should answer existential questions. I think "existence" is difficult to define in any testable manner. For example what are the criteria an entity must satisfy in order to claim it exists?
And at some extent it's "unclear" what one means by existence. Just because we know that protons are not fundamental particles, does it mean that protons don't exist?

If string theory is true (in one of the 10^{272,000} universes it predicts), then the elementary particles will be the strings.

 

[arivero]

yeah, existence is about god. To be precise, Saint Anselm argument for god has a translation to logic with a theorem of Von Neumann: "A Theory is consistent if and only if there exists a model". So if String Theory is a consistent set of axioms for each solution, all the universes exist. It is just a mathematical fact, unconnected to physics.