Re: Beams and time dependence

I should correct myself.

The first equation _is_ what is left after the time dependent part is
separated out - it just requires a bit more juggling.

"Tao" <not@xxxxxxxxxxxx> wrote in message
news:ej6Of.63007$494.45779@xxxxxxxxxxxxxxxxxxxxxxx
The wave in the first part does not satisfy the wave equation without
replacing ikx by i(kx+wt). I would say the first equation comes from
separating out the time dependent part of the function, but with two
arbitrary constants A and B, that would not be correct.

After replacing ikx by i(kx+wt) the two equations are the same to within
juggling some constants.

"Zinc Potterman" <zincnews@xxxxxxxxxxxxxxxxx (delete 123's to reply)>
wrote in message news:dq5egf$sfv$1@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
My physics book uses the expression;

psi(x) = A exp(ikx) + B exp (-ikx)

to model the incident and reflected components of a steady state beam of
particles of well defined momentum as they scatter normally from a
surface. (transmitted part not included)

It describes these as waves travelling in a region of zero potential.
In what sense are they *travelling* if there is no time dependence.

Earlier chapters introduce travelling waves as functions of the form

y(x.t) = Asin(kx+wt)
which I can follow.
Any tips links would be most welcome please.
Regards
Zinc

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