String Theory Demystified

Quiz Solutions 289
Chapter 11
1. c
2. b
3. b
4. a
5. c
Chapter 12
1. There are eight states, because there are eight transverse directions in spacetime
in the light-cone gauge.
2. These are the 16 states associated with the extra bosonic dimensions.
3. This keeps them in the left-moving sector.
4. i j i j
ij
⎡⎣ α , α ⎤ α α δ δ
m n ⎦ = ⎡⎣ , ⎤ m
m n ⎦ = m+ n,
0
5. 0
Chapter 13
1. φ = 0, ± 1
I J ⎡⎣ α , α ⎤ mδ
δ
m n ⎦ = m+ n,
0
2 A
2 4A
2. φ = 0,
m =− ( tachyon), φ =± 1,
m = > 0 ( not a tachyon)
3
3
3. φ = , ± φ
0 0
2 φ0
4. φ = 0,m
=−
2α
′
5. The stretching adds an energy 1
0 0
2α
′
αα
a a to the string where
2
1 ⎛ 2 − 1 ⎞
0 0 =
2 ′ ⎝
⎜
2 ′ ⎠
⎟
α αα
a a
a a x x
comes from the stretching between the branes.
πα
IJ