{[ promptMessage ]}

Bookmark it

{[ promptMessage ]}

445lec5

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

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

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 numbers required to specify the state.

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 ]}

### Page1 / 3

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

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

View Full Document
Ask a homework question - tutors are online