1
vote
1answer
58 views

A question about the Weyl transformation for the vertex operator of the closed-string tachyon

I met a problem of derving the Weyl transformation on the closed-string tachyon, Eq. (3.6.8) in Polchinski's string theory, vol 1, p 103. Given the vertax operator of the closed-string tachyon ...
1
vote
1answer
102 views

Vertex operator for closed string tachyon

The problem related to this post, but my question is even more elementary. In p 101 of Polchinski's string theory vol I, it is stated Using the state-operator mapping, the vertex operator for the ...
6
votes
1answer
397 views

Why does tachyon arise in bosonic string theory?

I am looking for precise mathematical and physical reasons which cause the presence of tachyon in bosonic string theory(specially closed bosonic string theory). Has it to do with the specific form of ...
5
votes
1answer
135 views

Why does unbroken supersymmetry imply the absence of tachyons?

Just a quick question, same as in the title. I'm trying to understand stable D-branes.
1
vote
2answers
390 views

How exactly do superstrings reduce the number of dimensions in bosonic string theory from 26 to 10 and remove the tachyons?

In bosonic string theory, to obtain the photon as the first excited state, the ground state must have a negative mass (tachyon). By applying $1 + 2 + 3 + \cdots = -1/12$, it can be shown (in a ...