Engineering and Applied Sciences Applied Physics 216 Lecture 5: Lecture 5

• School: Harvard University
• Department: Engineering and Applied Sciences
• Course: Engineering and Applied Sciences Applied Physics 216
• Professor: Jene Golovchenko

Document Summary

Ap 216 lecture 5: green"s functions, mathematical screening, fourier. Problem: to find the fourier transform of screened green function (cid:71) (cid:71) 0 e (cid:71) x (cid:71) (cid:71) x x (cid:71) x. This is screened coulomb potential which approaches the coulomb potential as 0. Why for fixed for fixed . x x (cid:71) (cid:71) x or as (cid:71) x (cid:71) As you will see we can"t define a ft without screening. There are physical arguments for doing this too. ( will fix (screen) the large distance, small k, behavior in the ft) Fourier transform pair dv dxdydz (cid:71) f k (cid:71) F x e (cid:71) (cid:71) ik x dv over all (cid:71) x space. 3 over all (cid:71) k space (cid:71) (cid:71) (cid:71) ik x f k e dv k dv k dk dk dk x y z. ) into expression for f(x (cid:112)) gives (all integrals over all space)