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Hi! This is my first post on these forums.

I'm having some problems with the split operator + FFT algorithm to solve the Schrödinger equation in time. A real Gauss curve in a zero potential environment should simply flatten out, but I get two peaks as the following Matlab run shows:

http://coelurus.thorntwig.se/data/pics/splitop.jpg" [Broken]

http://coelurus.thorntwig.se/data/tjo.m" [Broken]

The real problem I assume is that I have no experience at all in using FFT for numerical simulations similar to this method and I can't find any good references on it either.

Any hints, ideas or pointers would be much appreciated!

EDIT: I found a "solution", but I am not sure how to interpret it yet. I had a look in the WavePacket package and it seems that one has to shift both position and momentum space (in Matlab, one would use "fftshift") before and after each FFT. If anybody knows a rigid answer to that I would be overjoyed :) So yes, it works, but I'd like to see why...

I'm having some problems with the split operator + FFT algorithm to solve the Schrödinger equation in time. A real Gauss curve in a zero potential environment should simply flatten out, but I get two peaks as the following Matlab run shows:

http://coelurus.thorntwig.se/data/pics/splitop.jpg" [Broken]

http://coelurus.thorntwig.se/data/tjo.m" [Broken]

The real problem I assume is that I have no experience at all in using FFT for numerical simulations similar to this method and I can't find any good references on it either.

Any hints, ideas or pointers would be much appreciated!

EDIT: I found a "solution", but I am not sure how to interpret it yet. I had a look in the WavePacket package and it seems that one has to shift both position and momentum space (in Matlab, one would use "fftshift") before and after each FFT. If anybody knows a rigid answer to that I would be overjoyed :) So yes, it works, but I'd like to see why...

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