Christian Bracher

Assistant Professor, Atomic Physics and Quantum Theory

Ph.D. (Dr.rer.nat.), Technische Universität München, Germany, 1999
Diploma, Technische Universität München, Germany, 1995

Location:
Office: PH1, Room 206

California State University, Long Beach
Department of Physics & Astronomy
1250 Bellflower Blvd.
Long Beach, CA 90840-3901

Phone: (562) 985-5592 Office
Fax: (562) 985-7924
Email: cbracher@csulb.edu

Webpage:
http://www.csulb.edu/~cbracher/

Research Interest:
Matter Waves, Semiclassical Theory, Scattering.

Quantum mechanics describes the peculiar and often counterintuitive behavior shared by all objects when observed over sufficiently short distances and durations. A basic tenet of the theory is particle-wave dualism: Depending on the mode of observation, everything will display either particle-like or wave-like traits. For instance, radio waves transport their energy in small, identical packages called photons, while material objects like electrons and atoms, ordinarily thought of as particles, show quantum interference characteristic of waves. Using ultracold gases and superconductors, these matter waves may be observed on a macroscopic scale, and they are a very active field of study in atomic and condensed matter physics. (They also play an important role in modern particle physics, where they manifest themselves e.g. in neutrino oscillations.)

Some matter waves respond strongly to external fields - as an example, electrons are readily guided by electric and magnetic fields. The force exerted by these fields refracts and distorts the electron waves; a mathematical description is provided by scattering theory which generally examines the interaction of waves with their environment. Often, as in the electron microscope, the particle motion is described in classical terms instead, with electrons following distinct paths. Semiclassical theory elucidates the connections between the classical trajectory pattern and the propagation and interference of the corresponding matter waves. The theory is an extension and unification of ray and wave optics, and is grounded in modern mathematical catastrophe theory.