Re: waves vs. diffusion

["John S. Denker" <jsd@MONMOUTH.COM>]

At 12:46 PM 1/28/00 -0500, David Bowman wrote:
> a formal diffusion equation with an *imaginary* diffusion
> coefficient *is* a wave equation and has solutions that are waves.  The
> canonical case in point is the time-dependent Schrodinger equation.

Wiser words were never spoken!

In case anybody missed it, I'll restate it:  A parabolic partial
differential equation with real coefficients describes diffusion, not
waves.  If you put an "i" in the right place it becomes the Schrödinger
equation which describes waves, not diffusion.  Big difference.

If you want to make the S.E. look simple, you can set hbar=1 and c=1 and
mass=1, but you had better not set i=1.  No siree.