Maximum entropy method and spectral RMC

In experimental physics, it is usual to fit models to data to obtain useful physical information. The model may be quite detailed, and include information on the energies of microscopic states in the system (from which a continuous spectrum can be derived). In this kind of modelling, there are many more unknowns than data points, and many sets of microscopic states could give a good fit to the data. However, many of those sets are unphysical (for instance predicting negative numbers of states).

Information theory techniques such as the maximum-entropy method provide a way to choose a physical result from the infinite number of models with a small chi-squared value. I have been involved with developing methods for mobility spectrum analysis of semiconductor devices, which may be used on real systems. I have also developed a technique for extracting the phonon density of states from specific heat measurements. In that paper, I also developed a spectral reverse Monte-Carlo technique, which is an alternative to maximum entropy, without the assumptions of the entropy functional.

Jim Hague is a Senior Lecturer in Physics at the Open University in the UK. His main research interest is many body physics (both quantum and classical). He works on problems in biophysics, condensed matter theory and cold atoms. Jim teaches a wide range of physics topics, including relativity theory, electromagnetism and quantum physics.
If you are interested in doing a PhD in this area, please consult the Department of Physical Sciences website.

These pages are the personal responsibility of J.P.Hague. The views expressed here do not necessarily represent the views of the Open University. The University takes no responsibility for any material on these pages. Last update 18th August 2015.