Lecture 1 | String Theory and M-Theory
Why Physics Stack Exchange recommends it
Physics Stack Exchange users cite it as the source when asking about specific points Susskind makes, such as string mass and tension, the history of string theory's discovery, and Feynman diagram channels.
Recommended by 2 people across 2 different months, 2011 to 2023.
What it is
This is the first lecture of Leonard Susskind's Stanford Continuing Studies course on string theory and M-theory, recorded in 2010. He introduces the historical origins of string theory in meson scattering and builds up heuristic arguments about strings, mass, and tension.
What people said
Recommends Dilaton · 2011-08 · Physics Stack Exchange · on “What are the details around the origin of the string theory?”
I liked this video [this video] , where Susskind explains how he and some friends discovered string theory in the context of meson scattering. (This is just a very preliminary answer, the video is probably way below your level ... :-P, I will take it back as soon as it is superseded)
Recommends user135743 · 2023-09 · Physics Stack Exchange · on “Binding energy in lorentz boost”
In the first lecture here- M theory and string theory lecture 1, Leonard Susskind [this video] The lecturer gives a heuristic as to why a string of length $L$ has mass $L$ . Set all $h=c=1$ . His explanation is that relativistically the internal energy of mass $m$ is $m$ . On the other hand he uses the light cone trick in order to use nonrelativistic arguments to analyze the string: If you lorentz boost in the $z$ direction a lot, the energy becomes up to a const $p_{x,y}^2/p_z + m^2/p_z$ . Thus intuitively the mass here $p_z$ (Because of $p_{x,y}^2/p_z$ ; changing the momentum is hit by a factor of $p_z$ ), and the binding energy is $m^2/p_z$ since it doesn't depend on the momentum. Also a strin
Cites José D. · 2014-05 · Physics Stack Exchange · on “Leonard Susskind's videos. Which order?”
As a mathematics student with almost no modern physics background (just an introduction to relativity when I was in secondary school) I find Leonard Susskind's lectures videos (freely available in Youtube) very interesting but I am wondering, in which order should I watch them? Which courses first? These are the ones I have found in Youtube: Modern Physics: Quantum Mechanics ( [LINK] ) Modern Physics: Special Relativity ( [LINK] ) String Theory and M-Theory ( [this video] ) Einstein's General Theory of Relativity ( [LINK] ) Quantum Entanglements ( [LINK] ) Modern Physics: Classical Mechanics ( [LINK] ) Cosmology ( [LINK] ) The Theoretical Minimum ( [LINK] ) I would also appreciate if you could gi
Cites PNS · 2020-07 · Physics Stack Exchange · on “QFT and coordinate transformations”
I was going through this [this video] lecture, where Leonard Susskind explains that these two Feynman diagrams are considered to be equivalent in QFT: [LINK] One diagram explains the same phenomena in one possible way and the other describes the same thing in a different way. But, when I look at it, it seems an awful lot that if you take one of the diagrams, and rotate the entire space by $90$ degrees, then you get the second diagram. I know that one of the axis represents time, so it is not as easy as I described, but imagine drawing one of these on a paper and then rotating the whole paper. So, of course rotating the entire co-ordinate system is a coordinate transformation, but I don't know whe
Cites Bob A · 2022-01 · Physics Stack Exchange · on “String stretching mathematics in string theory”
In, Lecture 1 | String Theory and M-Theory [this video] by L. Susskind he says that some strings can be stretched to without the string snapping because they have a constant tension. If im not mistaken he was talking about non-relativistic strings. How would one show this mathematically?
Cites Eden Zane · 2022-05 · Physics Stack Exchange · on “Are there redundancy in Feynman diagrams for a particular scattering, in terms of rotation of the diagram?”
In the lecture [this video] (see after 00:11:40) Leonard Susskind discusses a particular instance of indication of redundancy in the Feynman diagrams of scattering of $\pi$ mesons via $\rho$ mesons. [LINK] He continues saying that if there is a Feynman diagram like that on the left, principles of QFT says that there is another one like that on the right. I suppose that what he is talking about is the different channels of the scattering, s-channel and t-channel. And he says, when people collected experimental data for the scattering, they found they seemed to overcount the diagrams, particularly the s-channel diagrams itself gives the experimentally observed value of the scattering. And in a late