Current Projects

My principal project is the Double-Bulb Rubidium Maser, which is a new atomic clock which will provide frequency stability comparable to the most stable clocks in a smaller and less expensive package.

Recently we have begun work a new type of atomic clock, the Coherent Population Trapping (CPT) Clock. This clock will eliminate the "light shift" which limits the stability of existing clocks through the use of coherent population trapping, in which the Rb atoms are placed into a "dark state" in which they no longer couple to the light but do couple to a microwave cavity and produce a clock output.

I also help supervise Marc Humphrey, a graduate student, working on the cryogenic hydrogen maser. The CHM will be useful both as a high stability clock, and as an apparatus for studying cold atomic collisions.

We have also been finishing a measurement with a room temperature hydrogen maser looking for violations of Local Lorentz Invariance (LLI) or Charge, Parity, and Time reversal (CPT) symmetries. By looking for dependence of the Zeeman frequency of the hydrogen atoms in our maser as the earth rotates and their quantization axis point in different directions relative to the fixed stars.

Finally, I have also been helping out trying to characterize and improve our use of laser diode arrays in optical pumping. of spin-1/2 nobel gases.

I am presently involved in three projects:

I was a graduate student in the lab of Professor Gerald Gabrielse in the Harvard Physics department. I trapped antiprotons and determined that their charge-to-mass ratio is the same as that of the proton to within one part in one billion. The results of the thesis work of Anton Khabbaz, the graduate student who took on the challenge of improving the measurement at CERN, have recently been published. The measurement is one order of magnitude better than mine!