
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
TTFTCNQ. These calculations led to the investigation of
acoustic plasmons in one dimensional conductors. He then
tackled the problem of superconductivity in the A15
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
selftrapping. 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, quasi2D 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 spinpolarized 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 longterm
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 lowdimensional 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, largescale parallel
computations, finitesize scaling, optimization, and
manybody interactions and invariants. 
Prof. Michael
Tammaro works in theoretical condensed matter physics
and Monte Carlo calculations. His investigations include
modeling of farfromequilibrium systems using techniques
of contemporary statistical physics, hierarchic rate
equations, Monte Carlo techniques, reactiondiffusion
equations, and master equations. Specific focus is on thin
film properties, such as diffusion, electromigration,
nonequilibrium phase transitions, transport in disordered
media, chemical wave propagaion, and chemical reactions on
surfaces. 
