Collective phenomena in correlated semiconductors, degenerate Fermi gases, and ferroelectrics

• Main Author: Conduit, C. J
• Format: Dissertation
• Language: English
• Published: University of Cambridge 2009

Degenerate semiconductors: Assuming that there is large number of degenerate conduction band minima provides a useful route to developing an exact analytical treatment of semiconductors. The new formalism, which was also verified computationally, gives an exact expression for the total electron energy, and provides convenient access to the electron dynamical response. Ultracold atomic gases: These are a new tool that offers investigators an exquisite level of control over a many-body systems. Firstly we show how an atomic gas could be used to unravel a long-standing mystery about textured superconductors, secondary we explore the properties of collective models, and thirdly we investigate a novel form of ferromagnetism. Critical phenomena in correlated quantum systems: As the temperature falls thermal excitations give way to quantum fluctuations. These can couple leading to unexpected phases; firstly we search for a putative textured phase that could pre-empt the first order ferromagnetic transition, and secondly predict a metaelectric phase transition in ferroelectrics.