Homework Help: Zwiebach page 292

1. Nov 26, 2007

ehrenfest

1. The problem statement, all variables and given/known data
In equation 14.81, why are the lower indices of the oscillators alpha^r and alpha^s not divided by 2 like they were in equation 14.77?

2. Relevant equations

3. The attempt at a solution

2. Nov 26, 2007

nrqed

In my edition, equation 14.81 has no alpha (it has integrals with exponentials) . But my equation 14.82 has the commutator of alpha^r and alpha^s and they have, respectively, the subscripts m/2 and n/2.
I am not sure if you have that.

3. Nov 26, 2007

ehrenfest

I'm sorry. I meant 14.80. Mine has subscripts of m and n (not divided by 2) so it must be a typo. That would make much more sense since the commutator of 14.82 in my book does have subscripts that are divided by 2.

Last edited: Nov 26, 2007
4. Nov 27, 2007

Jimmy Snyder

I'm pretty sure it's a typo. Here is Professor Zwiebach's errata page. It has his e-mail address where you can send him this one.

http://xserver.lns.mit.edu/~zwiebach/firstcourse.html" [Broken]

Last edited by a moderator: May 3, 2017