Theoretical Research Groups

Prof. Leonard Kahn 's research has spanned several areas. His early work involved the study of the surfaces of solids. Specifically, he studied the chemisorption of alkalis on metal surfaces. The technique that was used was the density functional formalism. He used this formalism to study hydrogen in metals, as well as defects in metals. The main thrust of the work was to calculate the electric field gradient in these imperfect materials. His attention then changed to the study of the optical properties of one dimensional conductors, such as TTF-TCNQ. These calculations led to the investigation of acoustic plasmons in one dimensional conductors. He then tackled the problem of superconductivity in the A-15 materials, looking for an alternative mechanism to explain their high temperature transition.

In the late 80's, Prof. Kahn became interested in nonlinear phenomena. This began as an interest in chaos and "strange attractors." With Ken Hartt, he developed some techniques for determining whether or not two sets of time series are dependent on common variables. While at Irvine, he noticed that the equations being used to describe nonlinear optics were very similar to those he had seen in studies of chaos. It turns out that very simple models contain a wealth of phenomena. This model of nonlinear optics is a useful platform for studying solitonic resonances, the temporal and spatial development of chaos, signal processing, and electron self-trapping. Prof. Kahn's interest in nonlinear optics continues. Specifically, he is examining layered structures to determine how electrical devices, such as diodes and transistors can be modeled by optical systems. He has had two seniors complete their senior research papers on this topic, as well as a Ph.D. thesis by Kelan Huang on nonlinear optics. Most currently, he is examining the effects of defects in the layered structure on the transmission properties of the system.

Prof. Chuck Kaufman works in theoretical physics, specializing in weak interactions, quantum electrodynamics, chaos, and turbulent media.
Prof. Alex Meyerovich works in theoretical condensed matter physics.
His most recent publications deal mainly with quantum transport and interference in systems with random boundaries. The applications include nanosystems, quantum size effect in conductivity, quasi-2D and multilayer systems, localization of ultracold neutrons in gravitational traps and electrons or hydrogen atoms on helium surface, etc. Prof. Meyerovich is also actively interested in low temperature physics, especially in the theory of Fermi and Bose liquids, quantum crystals, and superfluidity. He is the author of some of the pioneering papers in the field which is now known as physics of spin-polarized quantum systems. The focus here is on macroscopic quantum phenomena such as giant growth of transport coefficients with spin polarization of Fermi systems or anomalies in spin dynamics of Fermi liquids. Prof. Meyerovich maintains long-term collaboration with several leading experimental and theoretical groups in the U.S., France, The Netherlands, and the U.K.
Prof. Gerhard Müller works in theoretical condensed matter physics and in quantum chaos. His condensed matter research focuses on the dynamics of low-dimensional systems of localized or itinerant electron spins. For these studies he employs general methods (e.g. the recursion method) with a wide range of applications as well as special methods that are applicable only for completely integrable models (e.g. the Bethe ansatz). His quantum chaos research focuses on the characteristic signatures of integrability and nonintegrability in quantum mechanics as manifested in invariants (conserved quantities) derived from symmetries of via time average from arbitrary observables. Prof. Müller has written, in collaboration with colleagues and former students, tutorial materials for beginning graduate students on the following research topics: Recursion Method, Bethe Ansatz, Hamiltonian Chaos.
Prof. Peter Nightingale works in condensed matter theory, studying phase transitions and critical phenomena, critical dynamics, surface physics, and van der Waals clusters. Prof. Nightingale's work also includes computational physics, with a focus on classical Monte Carlo methods, quantum Monte Carlo methods, large-scale parallel computations, finite-size scaling, optimization, and many-body interactions and invariants.
Prof. Michael Tammaro works in theoretical condensed matter physics and Monte Carlo calculations. His investigations include modeling of far-from-equilibrium systems using techniques of contemporary statistical physics, hierarchic rate equations, Monte Carlo techniques, reaction-diffusion equations, and master equations. Specific focus is on thin film properties, such as diffusion, electromigration, non-equilibrium phase transitions, transport in disordered media, chemical wave propagaion, and chemical reactions on surfaces.