David B. Tanner, Ph.D.
Distinguished Professor of Physics
David Tanner's research group works in two primary areas: Optical properties of solids and Experimental Astrophysics. Optical effects in solids occur in the wavelength range from the far infrared through the near ultraviolet. The Tanner group has worked hard to achieve coverage over this very broad spectral range to measure small, often anisotropic, samples, with analysis to estimate the optical conductivity and dielectric function.
The study of the optical properties of high-temperature superconductors has been an important part of Tanner's research program. Among the results are the discovery of the non-Drude "midinfrared" absorption, the first observation of the collapse of the quasiparticle scattering rate at the superconducting transition, and the demonstration that spectral features thought to represent the superconducting energy gap were from other causes. In collaboration with colleagues in the Department of Chemistry, Tanner has also an interest in the structure, transport, optical, and luminescence properties of conductive polymers.
The Tanner group at the University of Florida is a member of a team conducting a search for axions. The discovery of the axion, or placing strong limits on its existence, would have profound implications for two of the most important problems in contemporary physics: (a) the origin of CP symmetry in the strong interactions, and (b) the composition of the dark matter that makes up approximately 30% of the mass of the universe. The experiment exploits the fact that axions may be stimulated to convert into microwave photons in a microwave cavity threaded by a large magnetic field. This detection method, first proposed by Pierre Sikivie of the University of Florida physics department, is the basis of an ongoing experiment at Lawrence Livermore National Laboratory.
Tanner is also part of the University of Florida's LIGO (Laser Interferometer Gravitational-Wave Observatory) project that studies gravitational waves. While the University of Florida's initial role in LIGO was to build and deliver the "input optics", following a long data-taking run LIGO is presently beginning an upgrade, called "advanced LIGO," that will increase the sensitivity tenfold. The University of Florida and the Tanner group will build the input optics for advanced LIGO and also be involved in data analysis, a major task during operations.