What about PHONONS?
OK so here's a little question that all this discussion has brought to mind. Do phonons, that is, modes of vibration of a lattice of particles (approximated as a continuous fluid), have a temperature?
Reif (in Fundamentals of Statistical and Thermal Physics) has a great...
Actually Order, I think we were kind of doing the same thing!
You were asking things like, is the definition
KE = \frac{1}{2}mv^2
consistent with the "intuitive" idea that the change in kinetic energy is invariant with respect to different reference frames (ie invariant with respect to...
The answer here might lie in the difference between exact and inexact differentials. An exact differential is the differential of a scalar function, call it F. For a function of two variables x and y, we have:
dF = P(x,y)dx + Q(x,y)dy
By the commutation of second order partial...
Reilly,
Thanks--your response is both encouraging and enlightening. I've been working over the summer and the past year or so to develop a very consistant and non circular approach to classical mechanics. I've been let down somewhat by books like Goldstein's "Classical Mechanics" which seem...
I have studied statistical mechanics using F. Reif's book, and learned a lot, but there are still a couple very fundamental questions which still elude me. If anyone would be willing to share some insight, I would really appreciate it!
So Reif early on discusses the fundamental postulate of...
Sounds like the second law of thermodynamics to me too. To properly understand the second law one must be careful and rigorous--there's a LOT of misinformation out there. Pretty much all of statistical mechanics (a formal statistical framework from which the original "laws of thermodynamics"...
\mu^3,
I once had the same question. Here's what I assume you're curious about. If the universe has existed for an infinite amount of time, then by the postulates of classical statistical mechanics, it should have already settled into an equilibrium situation (ie a maximum entropy state with...
Thanks so much for all the replies. Gallileo especially brings up a good point about the second order differential equation of motion. I suppose what I should interpret Liboff to mean is that, if at some instant (ie for some value of the parameter t) you know the position and velocity of a...
Hi,
I've had a question ever since my quantum classes that's pretty simple I guess, but still seems to elude me. So here it is:
One text I used for quantum (Liboff's "Introductory Quantum Mechanics") says that in classical mechanics, there is a "vector of the state" of a system, that...
The elegance of conserved quantities
Order,
Over the past 2 years, I've thought about several classical mechanics mysteries--including kinetic energy KE = \frac{1}{2}mv^2--all the time. In class when I'm supposed to be learning other things, on the crapper, on dates...you name it. And...