Gravity
- Consistent only if it includes gravity
- Unlike standard model: only if gravity is left out
9+1 dimensions
- Violent jittery quantum motion of a strong can pile up
- Only in 9+1D: delicate conditions met so that oscillation of all modes of every string precisely match each other and become undetectable
Supersymmetric moduli space
- Every fermion/boson has its boson/fermion
- Vacuum energy = 0
- Most of string theory research is about this plain
M-theory
- Not many theories, but many solutions
- Correspond to extreme values of the moduli (corner of the landscape)
- Continuously vary so that one morphs into any other
Line represents particles moving through spacetime
Sheets represent strings moving through spacetime
Closed string splitting into two
He suggested that the smooth, continuous world sheet is really a network or mesh of closely spaced lines and vertices. In other words it is a very complicated, but otherwise ordinary, Feynman diagram composed of a great many propagators and vertices.
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