PhD position

PhD Position at King's College London: Developing new computational approaches to tackle the quantum many-body problem in extended systems

This is to advertise a fully funded PhD position (with stipend and additional London weighting) open to UK & EU candidates to work at King's College London within the Theory and Simulation of Condensed Matter group, under the supervision of Dr. George Booth.
It is a curious fact that fully quantum mechanical predictions of the properties of isolated molecules can now be made with accuracy which rivals the most precise experimental spectroscopy techniques. However, when looking at extended systems, such as the interaction of a molecule with a solid surface, state-of-the-art computational approaches can often not even reach the accuracy required to deduce correct structures or interaction energies.
The aim of this ambitious research is to make progress in this area – to transfer the accuracy of quantum chemical approaches to the setting of extended systems, by development of new approximations and techniques which use the electronic wavefunction as the central quantity of the simulation. The wavefunction, despite being the first quantum variable which is introduced, is almost entirely neglected within computational simulations of extended systems. This is because of the exponentially large amount of information required to specify it, which has meant that alternatives such as the electron density has generally been used instead.
However, most of this complexity is artificial. For example, within insulating systems, the correlation length between electrons decays exponentially, and so approximations based on locality of electrons or embedding of correlation effects can be introduced, rendering it a tractable computational object. Additionally, parts of the wavefunction have a universal, analytic form (such as when two electrons occupy the same point), and so these parts of the wavefunction can be considered known, and removed from the required parameterization. Furthermore, clever optimization strategies can be developed, including Monte Carlo sampling of the wavefunction, and compact functional forms of the wavefunction, which can dramatically increase the potentiality of this approach.
These new ideas will be developed and then applied to real systems of significant technological interest, where current techniques are lacking, such as correlated transition metal oxide materials, and organic photoactive molecular crystals.
The project will have a large programming component, where these new methods will need to be coded and tested, before potential optimization for use on supercomputing resources. Furthermore, the successful candidate should have a strong background in modelling techniques and quantum many-body physics and/or chemistry.
King’s College, part of the University of London, is the fourth oldest university in England, and one of the top 30 universities in the world (2011/12 QS international world rankings). The Department of Physics is located on the Strand Campus, right in the heart of central London.
For further details contact Dr George Booth (george.booth@kcl.ac.uk). Prospective applicants are encouraged to apply as soon as possible.
http://psi-k.net/jobs/phd-position-at-kings-college-london-developing-new-computational-approaches-to-tackle-the-quantum-many-body-problem-in-extended-systems