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Atom trajectories 'blow up' at times #31

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ajkerr0 opened this issue Jun 16, 2016 · 2 comments
Closed

Atom trajectories 'blow up' at times #31

ajkerr0 opened this issue Jun 16, 2016 · 2 comments

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@ajkerr0
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ajkerr0 commented Jun 16, 2016 •
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cos_1point5_t_blowup
In particular when 6 member chain is driven at the end by a cosine force of angular frequency 1.5: the displacements get huge around 200 time units. There are also amplitudes near 100 time units that don't seem to be present in Dr. Mullen's plots, an indication that things are to blow up at later t?

Maybe this is an indication that my calculation isn't totally correct (seems to be closer to correct than before). Maybe this frequency is a resonant frequency that moves the chain large distances since the chain isn't 'tied down'? Could try adding a small potential to one of the inner atoms.
ajkerr0 referenced this issue Jun 16, 2016
@ajkerr0
Correct the displacement calculation
a7fc85c 
Make the necessary changes for 'correct' displacement calculations, which were addressed in #30.  The problem was in the integration.  Keep the new code in 'greens_func.py' while the old method is kept in 'greens_func_old.py'.  Add functionality to plot the displacements of every atom simultaneously.  Delete 'elementwise_gf.py' as that existed to test the construction of arrays by doing so element-wise which ended up not being the problem in the end.
@ajkerr0
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ajkerr0 commented Jun 16, 2016

The spikes seem to be very localized in time when you look at longer time ranges, different parameters such as driving frequency, etc.

@ajkerr0 ajkerr0 changed the title Atom trajectories 'blow up' at large times Atom trajectories 'blow up' at times Jun 16, 2016
@ajkerr0
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ajkerr0 commented Jun 17, 2016

The 'blow up' nature of the solutions seem to go away (or at least some of them) if you increase the resolution/sample size of the integrals.

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