There's a problem in Liboff's text "Introductory Quantum Mechanics - 3rd Ed."(adsbygoogle = window.adsbygoogle || []).push({});

On page 176 problem 6.12 states

"A particle moving in one dimension interacts with a potential V(x). In a stationary state of this system show that

(1/2) <x dV/dx > = <T>

where T = p^2/2m is the kinetic energy of the particle."

Liboff gives the answer but starts off with

"In a stationary state,

d<xp>/dt = (i/hbar)<[H,xp]> = 0

..."

Why? I.e. why is d<xp>/dt = (i/hbar)<[H,xp]> = 0 for a stationary state?

Pete

**Physics Forums | Science Articles, Homework Help, Discussion**

Dismiss Notice

Join Physics Forums Today!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

# Problem in Quantum Mechanics

**Physics Forums | Science Articles, Homework Help, Discussion**