445lec5 - PHYS 445 Lecture 5 - Fundamental postulate...

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

View Full Document Right Arrow Icon
PHYS 445 Lecture 5 - Fundamental postulate 5 - 1 © 2001 by David Boal, Simon Fraser University. All rights reserved; further resale or copying is strictly prohibited. Lecture 5 - Fundamental postulate What's Important: description of a state probability density of states Text : Reif Secs. 2.1 to 2.5 should be read independently Description of a state In classical mechanics , a 3D system of N particles without spin or any internal structure can be described by 6 N variables. positions: q 1 ... q N (coordinates are the degrees of freedom) momenta: p 1 ... p N Knowing these quantities at a particular time, one can use Hamilton's or Newton's equations to predict their values at all later times. The coordinate variables q are called the degrees of freedom f of the system. Here, there are 3 N coordinates so f = 3 N . The positions and momenta of the particles form the phase space of the system. In spin systems on a fixed lattice, the degrees of freedom are the spin orientations: ↑↓↓↑↑↑↓↓↓↑↑↓↑↓↑↑ f degrees of freedom In quantum mechanics, the number of degrees of freedom is the number of quantum
Background image of page 1

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

View Full DocumentRight Arrow Icon
Image of page 2
This is the end of the preview. Sign up to access the rest of the document.

This note was uploaded on 09/07/2009 for the course PHYS 445 taught by Professor Davidboal during the Spring '08 term at Simon Fraser.

Page1 / 3

445lec5 - PHYS 445 Lecture 5 - Fundamental postulate...

This preview shows document pages 1 - 2. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online