Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Homework Help: Zwiebach page 292

  1. Nov 26, 2007 #1
    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. jcsd
  3. Nov 26, 2007 #2


    User Avatar
    Science Advisor
    Homework Helper
    Gold Member

    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.
  4. Nov 26, 2007 #3
    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
  5. Nov 27, 2007 #4
    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
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook