About
CV
Research Interests
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I have many and varied research and engineering interests. These include topics in gravitational waves, astrophysics, engineering and control systems, and nonlinear dynamics.
I am interested in continuing data analysis for gravitational wave (GW) data. In the past, I have carried out analysis of LIGO data using the RIFT techniques of Richard O'Shaughnessy and Jacob Lang, especially looking at possible high mass binary black holes. At Vanderbilt, and in our LIGO group, we were exploring analysis using the Open Science Grid---a shared high-throughput computing infrasture making use of idle or designated compute nodes on existing clusters.
I would like to have the opportunity to analyze data from pulsar timing array exeperiments--- though they are not in my experience but I would welcome the opportunity to study these experiments and data.
I have some experience looking at novel sources of gravitational waves for the planned, space-based gravitational detector LISA. With Prof. Kelly Holley-Bockelmann, motivated by the discovery of hot jupiter expolanets, we started to look at GWs from exoplanets. These did not rise to the current estimate of detectability, but close. And with Emanuele Berti and Kaze Wong we wrote a critique paper that said one could detect expolanets.
For my interests and research in GWs, I have been able to learn and support the numerical relativity open access code Einstein Toolkit . The current generation of numerical relativity codes are note sensitive enough to take advantage of the likely very nigh signal-to-noise sources that next generation detectors will be seeing. I would like to explore some novel ideas based on nonlinear dynamics techniques and the use of Lie operator methods...possibly along the lines of superconvergent perturbation theory.
I also wonder if it is possible that Post-Newtonian / Post-Minkowskian expansions might not be improved with canonical/sympletic transformations.
There is an advanced, if difficult Mathematica toolkit called xAct that is very powerful but also very difficult to use. I would like to explore this tool for many of the calculations in GR and wormholes that we come across, e.g. the stability or dynamics of the wormhole throat.
Also as part of my research in GW and my continued interest, with Kelly, Tom Kephart, and James Dent, we explored the GWs from a compact object passing back and forth through a traversable wormhole. Our published paper was the smallest, first step and showing an example of a system and its GW waveform---showing that these very speculative and exotic objects could be detectable in the LIGO frequency band.
Along those lines, I would be intersted in exploring the behavior of the exotic matter that opens the wormhole through in these Visser-like traversable wormholes. As friends who study General Relativity (GR) often say, it is possible to pose what seems an easy question in GR that is very difficult to answer or even address. I think exploring the motion of so-called exotic matter, and its likely fluid behavior as normal matter passes through it is very interesting. The form of the energy-momentum tensor for the exotic matter also descides the motion of the throat itself---growing or shrinking or osciallating in radius.
Exploring the systems that are purported to have exotic matter like properties would also be important. Is there any kind of imagined or real experiment that might explore the wormhole "effect" .
I spent many years working on and leading the operations of the Vanderbilt free-electron laser (FEL) with mentors Charles Brau, Marcus Mendenhall, and Glenn Edwards, as well as the many technicians and FEL operators with their years of experience. My research was in the "injector"---those electron source and magnetic elements before the S-band linear accelerator. The elements include a LaB6 heated cathode, placed precisely inside a single cavity RF gun and externally heated. The difficulty there is that electrons are pulled out of the cathode, and accelerated, but much of the beam turns around as the electric field reverses sending electrons back toward the cathode. Without a special magnet that bends the electrons away from the cathode, the returning electrons would lead to run-a-way heating of the cathode. The exiting electrons go on to pass through a bend magnet called an "alpha magnet," as the electron path makes an greek letter alpha shape. The beam enters at 40.7 degrees and exits at the same, with a slit system the momentum spread of the electron bunch is reduced to about 10% around the 1.1 MeV/c bunch momentum. This beam is injected into the S-band linac, and with beam loading, the final beam energy is tunable from 30 to 45 MeV, which is used to change the laser wavelength.