ChatterBank1 min ago
What Are Strings Made Of?
18 Answers
I've been aware of string theory for many moon cycles now but only today decided to research it online to better educate myself. A couple of things intrigue me, like:
- What is the string fabricated from that allows harmonic vibrations of 'it' to form subatomic particles? ~ (Isn't true that we think of things as elemental until we get a powerful enough microscope?) ~ Although I know string theory is different because it predicts it via 'beauty in math,' so what does the math tell us about the composition of the string?
- (sub question) Do strings have electromagnetic charge or a gravitational 'pull'? Again because I can't decrypt the math involved, I'm blind.
What are your thoughts?
IHI
- What is the string fabricated from that allows harmonic vibrations of 'it' to form subatomic particles? ~ (Isn't true that we think of things as elemental until we get a powerful enough microscope?) ~ Although I know string theory is different because it predicts it via 'beauty in math,' so what does the math tell us about the composition of the string?
- (sub question) Do strings have electromagnetic charge or a gravitational 'pull'? Again because I can't decrypt the math involved, I'm blind.
What are your thoughts?
IHI
Answers
1 to 18 of 18
Following on from this, what are magnetic field lines made of ?
20:26 Tue 05th Mar 2013
In quantum field theory and its extensions including string theory, the electric charge is a generator of a U(1) symmetry which should be promoted to a local symmetry i.e. gauge symmetry.
In string theory, the U(1) symmetry and the gauge field often appear as parts of the low-energy effective action. This could be enough to answer the question: we reduce the problem to the same problem in the approximate theory - quantum field theory.
I thought everyone knew that.
In string theory, the U(1) symmetry and the gauge field often appear as parts of the low-energy effective action. This could be enough to answer the question: we reduce the problem to the same problem in the approximate theory - quantum field theory.
I thought everyone knew that.
//Isn't true that we think of things as elemental until we get a powerful enough microscope?//
Not quite - we think there is underlying structure wher patterns arise
There were patterns in the elements that suggested there was an underlying structure and indeed we discovered that the arrangement of subatomic particles was responsible for that pattern.
There was structure in subatomic particles Kaons and Pions and all the other -ons and the standard model of quarks and leptons explained this
There is structure in quarks and leptons - the idea on string theory is that strings are purely fundamental and it is only their 'vibration' mode that determines the nature of a particle.
That being said IMO whether string theory is truely science is questionable - to be science a theory must be testable and proposed strings are so small I've yet to see a convincing test that we could perform to prove or disprove their existance.
Of course I would say that because I come from an experimental tradition - the theorists would talk you to death with excuses about untestable hypotheses.
second one - no - they carry those forces in their guises as other paticles as in Quantum electrodynamics (QED) ( well gravity maybe more complex the graviton is still theoretical)
Not quite - we think there is underlying structure wher patterns arise
There were patterns in the elements that suggested there was an underlying structure and indeed we discovered that the arrangement of subatomic particles was responsible for that pattern.
There was structure in subatomic particles Kaons and Pions and all the other -ons and the standard model of quarks and leptons explained this
There is structure in quarks and leptons - the idea on string theory is that strings are purely fundamental and it is only their 'vibration' mode that determines the nature of a particle.
That being said IMO whether string theory is truely science is questionable - to be science a theory must be testable and proposed strings are so small I've yet to see a convincing test that we could perform to prove or disprove their existance.
Of course I would say that because I come from an experimental tradition - the theorists would talk you to death with excuses about untestable hypotheses.
second one - no - they carry those forces in their guises as other paticles as in Quantum electrodynamics (QED) ( well gravity maybe more complex the graviton is still theoretical)
ZM "I thought everyone knew that. " - I think I skipped that lecture to stop my brain from hurting :)
JTP - You're teasing me with useful and interesting facts but might I conjugate an answer you're trying to give; string theory has huge flaws such as its non-experimental conclusions and (in my mind a leap of faith) it needs to summon 10 or 11 dimensional space for the maths to fit correctly as the 'grand unifying theory of everything.' But we are lead to believe that an, as yet, unclassified force allows a looped string of pure energy to vibrate and coalesce structured particles with set properties... Right?
I maybe leaping across massive important mathematical principles that apply my connections, but what evidence does string theory propose for how the looped energy started to vibrate and what maintains it? Is it a fixed amount of perpetual limitless energy, trapped in it's particle shell?
E=mc2 says matter and energy are equal, they can be converted from one form to the other but never lost, destroyed or even created. What would happen (theoretically) if you were able to collapse the wave function of a gluon? Or more simply, is it possible to separate string from particle?
Wow, I'm having to stop myself from flooding this post with dozens of questions... One step at a time :) Can you address any of these points?
(My terminology is probably highlighting my severe lack of diciplined mathematical education! Sorry!)
IHI
JTP - You're teasing me with useful and interesting facts but might I conjugate an answer you're trying to give; string theory has huge flaws such as its non-experimental conclusions and (in my mind a leap of faith) it needs to summon 10 or 11 dimensional space for the maths to fit correctly as the 'grand unifying theory of everything.' But we are lead to believe that an, as yet, unclassified force allows a looped string of pure energy to vibrate and coalesce structured particles with set properties... Right?
I maybe leaping across massive important mathematical principles that apply my connections, but what evidence does string theory propose for how the looped energy started to vibrate and what maintains it? Is it a fixed amount of perpetual limitless energy, trapped in it's particle shell?
E=mc2 says matter and energy are equal, they can be converted from one form to the other but never lost, destroyed or even created. What would happen (theoretically) if you were able to collapse the wave function of a gluon? Or more simply, is it possible to separate string from particle?
Wow, I'm having to stop myself from flooding this post with dozens of questions... One step at a time :) Can you address any of these points?
(My terminology is probably highlighting my severe lack of diciplined mathematical education! Sorry!)
IHI
A string vibrates naturally anyway -- think of it just like a violin string, or perhaps a bracelet made of string. So the vibrations occur just as a natural property of the string. This means that it's possible that at last we have reached a fundamental level of nature. The dimensions in which the string live aren't so much a leap of faith as forced on you by the mathematics - i.e if these things are in any way physical, then number of dimensions = 10. I can't quite prove this yet (ask me on Thursday) but it's anyway one of those things that you can't escape if you want this to be a real and worthwhile theory.
The particles themselves then become vibrations of the string, so that there is no way to separate particle from string.
The vibrations themselves are due to whatever the conditions imposed on the string are. So like a violin string again, if you demand that its ends be fixed then you can still allow vibrations, and the energy to drive these would just live in the string. It's due to the String's Tension, or if it has none, then its "momentum", whatever that means for a string.
There's not much that can be done to address JTP's points. At the moment even fairly conservative estimates would suggest that a string has sizes in the region of maybe 10^-30 metres or even orders of magnitude smaller. The LHC can probe down to distances of no smaller than 10^-18 metres, I think, in which case it's about 1 trillion times too weak to get anywhere near to string theory scales. So we're a long way off if ever from confirming string theory.
All that said it's still worth pursuing, both because from a mathematical point of view it's quite wonderful and because you never know, it will make an experimentally testable prediction eventually.
The particles themselves then become vibrations of the string, so that there is no way to separate particle from string.
The vibrations themselves are due to whatever the conditions imposed on the string are. So like a violin string again, if you demand that its ends be fixed then you can still allow vibrations, and the energy to drive these would just live in the string. It's due to the String's Tension, or if it has none, then its "momentum", whatever that means for a string.
There's not much that can be done to address JTP's points. At the moment even fairly conservative estimates would suggest that a string has sizes in the region of maybe 10^-30 metres or even orders of magnitude smaller. The LHC can probe down to distances of no smaller than 10^-18 metres, I think, in which case it's about 1 trillion times too weak to get anywhere near to string theory scales. So we're a long way off if ever from confirming string theory.
All that said it's still worth pursuing, both because from a mathematical point of view it's quite wonderful and because you never know, it will make an experimentally testable prediction eventually.
Good answer, fair comment. But referring back to the Title question, what are they made of? I'm hoping you wont insist that the string is a medium and the vibration is the particle so they are as one!! Is it looped energy? Coiled up in higher dimensional space? How does gravity actually fit in? (I'm buy books I promise, I promise. I just can't read them quick enough!)
IMO I think the theory will remain our number one guess for a long time and well done the brains who worked it out. I do fall on the side of JTP though, facts of science and laws of the Universe can only be regarded as such by producing consistent data from repeated experiment tests to prove the theory correct.
IMO I think the theory will remain our number one guess for a long time and well done the brains who worked it out. I do fall on the side of JTP though, facts of science and laws of the Universe can only be regarded as such by producing consistent data from repeated experiment tests to prove the theory correct.
If a guitar string is plucked it will vibrate at a fundamental frequency. Harmonics are also produced in the string, albeit with smaller amplitudes. The guitar string is a spring-mass system with a certain mass-per-unit length and tension. The force involved is the electromagnetic force.
Subatomic particles have properties of mass, charge, spin and flavour. An atom is made up of electrons and quarks, both have zero volume as far as we know. If these fundamental particles are considered to be one-dimensional strings, rather than than points, then the different modes of vibration can account for the above properties.
Subatomic particles have properties of mass, charge, spin and flavour. An atom is made up of electrons and quarks, both have zero volume as far as we know. If these fundamental particles are considered to be one-dimensional strings, rather than than points, then the different modes of vibration can account for the above properties.
Oh yes, in answer to the original question, the strings are made of... well, strings. They are meant ideally to be the furthest scale you can reach - so just like in the Standard Model an electron is made of itself, the strings are made of themselves. So they are the ultimate fundamental object. Unless of course you go to Branes... anyway.
If you believe the maths, gravity pops out of String Theory rather than String Theory being invented to describe gravity. You do quantum mechanics on the String and basically if it works it has to be a theory of Gravity. Hard to justify that, perhaps, without going to the maths. But the point really is that you don't have to do much work to fit gravity into String Theory, although we are still waiting for the guy to come along who can turn this into something useful. Lots of people working on it though!
If you believe the maths, gravity pops out of String Theory rather than String Theory being invented to describe gravity. You do quantum mechanics on the String and basically if it works it has to be a theory of Gravity. Hard to justify that, perhaps, without going to the maths. But the point really is that you don't have to do much work to fit gravity into String Theory, although we are still waiting for the guy to come along who can turn this into something useful. Lots of people working on it though!
Secretly I'm on a mission to be that very man Jim! But noone will believe that IHI got a Nobel prize for physics :)
"...in answer to the original question, the strings are made of... well, strings..."
I knew it! Didn't I say you'd perplex me like this!! I don't question that the fundemental building 'block' of matter will be indivisble and in 1 dimension, for it makes perfect sense. Instead of the mathematical models of strings and it's implied charicteristic vibration, does the theory discuss how it is able to be at all? Is it pure energy? Fillement of matter? Or perhaps a fusion of the two?
There is a finite number of states matter can be in, solid, liquid, gas, plasma... and Bose-Einstein condensate and a couple more maybe. So we have those forms or energy that must make up the string. If none of these things then what is it? Is connected to the cosm. constants and in some way just a one dimensional force?
IHI
"...in answer to the original question, the strings are made of... well, strings..."
I knew it! Didn't I say you'd perplex me like this!! I don't question that the fundemental building 'block' of matter will be indivisble and in 1 dimension, for it makes perfect sense. Instead of the mathematical models of strings and it's implied charicteristic vibration, does the theory discuss how it is able to be at all? Is it pure energy? Fillement of matter? Or perhaps a fusion of the two?
There is a finite number of states matter can be in, solid, liquid, gas, plasma... and Bose-Einstein condensate and a couple more maybe. So we have those forms or energy that must make up the string. If none of these things then what is it? Is connected to the cosm. constants and in some way just a one dimensional force?
IHI
The states of matter really apply at a macroscopic level. An atom isn't really solid, liquid or gas, but large collections of them are one of the three for example. So the string, which is many times smaller than an atom, can certainly not be characterised in that sort of way.
I think that given that the theory is still not understood fully it would be dangerous to say, but it's wrong to think of strings as having any substructure. Everything is made from them, rather than the other way round. So is it a filament of matter? Well, sort of perhaps, but the point is that matter is made from strings and not the other way round!
I think that given that the theory is still not understood fully it would be dangerous to say, but it's wrong to think of strings as having any substructure. Everything is made from them, rather than the other way round. So is it a filament of matter? Well, sort of perhaps, but the point is that matter is made from strings and not the other way round!
Sorry I didn't have much time to get to this post yesterday.
With regard to what magnetic field lines are made of - these are mathematical constructs, handy ways of looking at electromagnetism that really should be done away with but are too useful.
At a small scale forces are generally seen as carried by an exchange of virtual particles, the bosons.
Virtual particles flash in and out of existance in particle and anti-particle pairs - the more massive a virtual particle the shorter its life.
Electromagnetism is carried by photons, these are massless so the range is effectively inifinite.
The weak force is carried by W and Z bosons which have mass so this can only act over a short range.
From the nature of the questions you ask you seem to be in that difficult stage where you're fairly famillar with the topics at the popular science level that most TV programs go to but not ready (or interested) at a formal mathematical academic level.
If that is the case I could strongly recommend this book
http://
One of the best I've read in explaining some of the more modern concepts in the field - but still very accessible even if it is 10 years old now
With regard to what magnetic field lines are made of - these are mathematical constructs, handy ways of looking at electromagnetism that really should be done away with but are too useful.
At a small scale forces are generally seen as carried by an exchange of virtual particles, the bosons.
Virtual particles flash in and out of existance in particle and anti-particle pairs - the more massive a virtual particle the shorter its life.
Electromagnetism is carried by photons, these are massless so the range is effectively inifinite.
The weak force is carried by W and Z bosons which have mass so this can only act over a short range.
From the nature of the questions you ask you seem to be in that difficult stage where you're fairly famillar with the topics at the popular science level that most TV programs go to but not ready (or interested) at a formal mathematical academic level.
If that is the case I could strongly recommend this book
http://
One of the best I've read in explaining some of the more modern concepts in the field - but still very accessible even if it is 10 years old now
At this level any of these terms are merely labels given by the theorists to make the maths work. Strings, Branes, 11d, Calabi yau etc are merely theorists terms to try and visualise things. Something needs to be there to match observation or indeed projected observation so they give it a name. Not saying it's a load of old pony just a current path of thinking. I share jake's doubts about the string theory etc but I don't have anything better. Brian Greene's "the Elegant Universe" is worth a read might fill some gaps.
http://
http://
Supersymmetry and String Theory are both weird things. Having taken courses in them I could provide you with about 5 million reasons (exaggerating) why they ought to turn out to be true in the end, but of course it's experiment that counts and we haven't seen either of them yet.
I'm told by SUSY researchers that we shouldn't really be expecting to see it just yet, actually, but if in five years' time or so it's still a complete blank then the theory should be written off at least at this scale. I'm not really a fan of it either, for slightly different reasons (It's bloody hard) but you can't blame people for trying to seek attractive solutions to real problems.
I'm told by SUSY researchers that we shouldn't really be expecting to see it just yet, actually, but if in five years' time or so it's still a complete blank then the theory should be written off at least at this scale. I'm not really a fan of it either, for slightly different reasons (It's bloody hard) but you can't blame people for trying to seek attractive solutions to real problems.
@JTP
You're right. My level is of a TV documentary 'couch scientist'!! However, my interactions on AB have made me realise my fruitless knowledge despite my fertile learning centre's of my brain. I've therefore decided to get my A Levels in Maths and Physics and (if i can cope) a degree in physics to solidify my knowledge to draw better conclusions on some of my ideas.
I've many theories on modern scientific problems but without the graft needed to educate myself with all the physics and maths, I'll never be able to convince others of, or even understand, my own theories!!
Stay tuned, IHI's getting schooled ;) x
You're right. My level is of a TV documentary 'couch scientist'!! However, my interactions on AB have made me realise my fruitless knowledge despite my fertile learning centre's of my brain. I've therefore decided to get my A Levels in Maths and Physics and (if i can cope) a degree in physics to solidify my knowledge to draw better conclusions on some of my ideas.
I've many theories on modern scientific problems but without the graft needed to educate myself with all the physics and maths, I'll never be able to convince others of, or even understand, my own theories!!
Stay tuned, IHI's getting schooled ;) x
1 to 18 of 18
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