String Theory & Elementary Particles: What's Real?

In summary, string theory is a theory that suggests that elementary particles are just excitations of strings. It is still in its infancy, and has not been fully verified, but it is consistent and predicts many universes.
  • #1
Jupiter60
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TL;DR 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?
 
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  • #2
Jupiter60 said:
does it mean that elementary particles like photons, electrons, and quarks don't really exist

Of course not.

Jupiter60 said:
does it mean they do but are made of cosmic strings

String theory has nothing to do with cosmic strings.
 
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  • #3
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?
 
  • #4
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.
 
  • #5
Jupiter60 said:
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?
 
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  • #6
Vanadium 50 said:
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.
 
  • #7
Asked and answered

Jupiter60 said:
does it mean that elementary particles like photons, electrons, and quarks don't really exist

Vanadium 50 said:
Of course not.
 
  • #8
Jupiter60 said:
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.
 
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  • #9
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.
 
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  • #10
Jupiter60 said:
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.
 
  • #11
McFisch said:
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.
 
  • #12
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 [itex]10^{272,000}[/itex] universes it predicts), then the elementary particles will be the strings.
 
  • #13
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.
 

1. What is string theory?

String theory is a theoretical framework in physics that attempts to reconcile the theories of general relativity and quantum mechanics. It proposes that the fundamental building blocks of the universe are not particles, but tiny, vibrating strings.

2. How does string theory explain the nature of particles?

In string theory, particles are not considered to be point-like objects, but rather tiny strings that vibrate at different frequencies. The different modes of vibration correspond to different types of particles, such as electrons or quarks.

3. Is string theory a proven theory?

No, string theory is still a theoretical concept and has not been proven through experiments. However, it is a widely studied and researched area of physics, and many scientists believe that it has the potential to provide a unified theory of physics.

4. What are the implications of string theory?

If string theory is proven to be true, it would have significant implications for our understanding of the universe. It could potentially explain the existence of gravity, provide a unified theory of all forces, and offer insights into the nature of space and time.

5. How does string theory relate to other theories in physics?

String theory is often seen as a candidate for the theory of everything, as it attempts to reconcile the theories of general relativity and quantum mechanics. It also incorporates elements of other theories, such as supersymmetry and extra dimensions, to provide a more comprehensive understanding of the universe.

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