This program was used to generate several pretty graphs for my Master's thesis, "Vibration-Dependent Quantum Transport". It is based on an approach previously derived by Karsten Flensberg in "Tunneling broadening of vibrational sidebands in molecular transistors," Phys. Rev. B 68: 205323.

The core idea is to study systems where some sort of system (which otherwise commutes with the electron operators) directly modulates the hopping amplitude for those electrons. Examples given in my thesis include molecular motors and carbon nanotubes, but the techniques might also be developed in superconductor technology, perhaps by using a sensitive magnetic flux system like a flux qubit to control the magnetic flux through two Aharanov-Bohm rings sitting to either side of an electron dot. The program simply does not assume that the system must be a harmonic oscillator, or even that it begins in a thermal state, and only really assumes that there are thermalizing reservoirs to either side.

However, the examples given in this directory use harmonic oscillators. If there is a central surprise, it is that the sidebands seen in the flensberg.py example are not seen in the linear.py example, but there is a thermal broadening as seen in falloff_highT.py and an apparent "dip" in that broadening seen in falloff.py.

The file structure is a simple Python module; it is intended to run on Python 2.7.3 with access to the Python packages for scipy (and therefore numpy) and Gnuplot -- the latter is used only by the examples, and can be replaced with other packages (I made significant use of matplotlib when browsing around phase space at low resolutions).

This means that under Ubuntu the dependencies can probably be entirely installed via:

sudo apt-get install python python-gnuplot gnuplot python-scipy

The examples assume a Unix environment, namely a /tmp folder into which results are printed as postscript files.

The examples can be run by simply being in the core directory and typing e.g. python linear.py into the console -- the invibro subdirectory should automatically be loaded and compiled.

This project was authored by Chris Drost of drostie.org. To the extent possible by all laws in all countries, I hereby waive all copyright and any related rights under the Creative Commons Zero (CC0) waiver/license, which you may read online at:

http://creativecommons.org/publicdomain/zero/1.0/legalcode

This means that you may copy, distribute, modify, and use my code without any fear of lawsuits from me. It also means that my code is provided with NO WARRANTIES of any kind, so that I may have no fear of lawsuits from you.

This waiver/license applies to all of the code in the project as well as this particular file.