hw03sol

# hw03sol - Introduction to Quantum and Statistical Mechanics...

This preview shows pages 1–2. Sign up to view the full content.

1 Introduction to Quantum and Statistical Mechanics Homework 3 Solution Prob. 3.1. (a) x ˆ and 2 ˆ x commutate, so )] ( ˆ , ˆ [ x V x = 0 (4 pts) (b) p x ω m x x ω m i x V p ˆ ˆ )] ( ˆ , ˆ [ 2 0 2 0 = = h , where V ˆ is the same as in (a). (4 pts) (c) ] ˆ , ˆ [ 2 p p = 0 (4 pts) (d) 0 2 2 ˆ ˆ ˆ ˆ ˆ ˆ ] ˆ ˆ , ˆ ˆ [ 2 2 2 2 2 2 2 2 2 2 2 2 2 = + + = + = = x x x x x x x x x x x x x x p x p x p x x p p x h h h (4 pts) Prob. 3.2 For the momentum operator p ˆ , (a) k x i p h h = = ˆ (4 pts) (b) ( ) ( ) x ik k x ik p 0 0 0 exp exp ˆ h = . Therefore the eigenfunction is the plane wave function with the corresponding eigenvalue of 0 k h . Notice k 0 is a continuous parameter. (5 pts) (c) ( ) ( ) ( ) 0 0 0 0 ˆ k k k k k k k k p = = δ δ δ h h . Therefore the eigenfunction is the delta function with the corresponding eigenvalue of 0 k h . Notice k 0 is a continuous parameter. (5 pts) (d) The Fourier transform of the plane wave function in the x space is the delta function in k space. Both the plane wave function and the delta function with continuous k0 can form a complete set of functions to express arbitrary nonpathological functions.

This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document
This is the end of the preview. Sign up to access the rest of the document.

{[ snackBarMessage ]}

### What students are saying

• As a current student on this bumpy collegiate pathway, I stumbled upon Course Hero, where I can find study resources for nearly all my courses, get online help from tutors 24/7, and even share my old projects, papers, and lecture notes with other students.

Kiran Temple University Fox School of Business ‘17, Course Hero Intern

• I cannot even describe how much Course Hero helped me this summer. It’s truly become something I can always rely on and help me. In the end, I was not only able to survive summer classes, but I was able to thrive thanks to Course Hero.

Dana University of Pennsylvania ‘17, Course Hero Intern

• The ability to access any university’s resources through Course Hero proved invaluable in my case. I was behind on Tulane coursework and actually used UCLA’s materials to help me move forward and get everything together on time.

Jill Tulane University ‘16, Course Hero Intern