I’m currently reading Brian Greene’s book The Elegant Universe (~2000), attempting to get to grips with ST. I’m about 1/3 of the way through, and I think I need some stuff clarified before I proceed much further. I had a bit of an issue with what I knew about ST before starting this book, but I’m afraid his rather enthusiastic take on it is not exactly sweeping me along the belief pathway. However the first 3 chapters explaining relativity were very good indeed.
1/ he hasn’t explicitly said whether the strings are open or closed, but every diagram so far has shown them as closed. The Wikipedia article says they can be either in various circumstances. Is this something that’s only been clarified since the book was published?
2/ he says that various modes of vibration of the strings correspond to various fundamental particles (electron, quark, graviton etc). By vibration does he mean a literal physical vibration? If so I can’t grasp what that even means for an infinitely-thin string. Is it that the term “vibration” is merely a handy analogy, like the spin of an electron, or is it actually a physical vibration in some sense?
3/ and does that mean that if the string comprising an electron, say, can have its mode of vibration changed by some means, that it instantly transforms into a different type of particle?
4/ vibrations in real string have only wavelength, amplitude and frequency. This does not seem to be enough variables to cope with all the fundamental particles known about, let alone the second set needed for supersymmetry. But perhaps this is an artefact of the vibrations being just an analogy, there are more degrees of movement available for a 1-dimensional entity?
I’m sure there are more to come that I can’t think of right now, but thanks to anyone who can help me along a bit here.