Description:

Special AMO/Small Scale Fundamental Physics Seminar

UCLA

February 16, 2017, 2:00 PM, F160

Abstract: 

Cold atoms and ions are exciting systems for a variety of measurements of
fundamental physics. Radio frequency traps open up experiments with both large
ensembles of ions, e.g. in cold chemistry, and experiments with few or single
ions, such as in quantum computation, optical clocks, and tests of fundamental
physics, where ultimate quantum control matters. Optical traps enable
complementary experiments with neutral atoms.

I will first describe recent results from our work on cold chemistry
and cold molecular ions using a hybrid atom--ion.
We have developed an integrated time-of-flight mass spectrometer, which allows
for the analysis of the complete ion ensemble with isotopic resolution.
With this new ability, we have significantly enhanced previous studies of cold
reactions and found unexpected, new reactions. Further, we demonstrated a
proof-of-principle implementation of non-equilibrium physics in our hybrid trap.
Current work aims at demonstrating rotational cooling of molecular ions.

Next, I will report our recent results in the search for the
nuclear isomeric transition in thorium-229. This transition in the
vacuum-ultraviolet regime (around 7.8 eV) eludes nuclear physics techniques
but becomes accessible to lasers. It is better isolated from the
environment than electronic transitions making it a very promising candidate for
future precision experiments, such as a nuclear clock and tests of fundamental
constants. Our approach employs a direct search with thorium-doped crystals.
In a first experiment with synchrotron radiation (ALS, LBNL), we were able to
exclude a large region of possible transition frequencies and lifetimes.
Currently, we continue our efforts with enhanced sensitivity using a pulsed VUV
laser system. Additionally, theoretical considerations of possible transition
energies and lifetimes will be presented.

I will conclude with two proposed projects of new quantum systems for
fundamental physics tests and quantum-assisted technology. The first project
will introduce highly-charged ions into the ultra-cold regime and make them
accessible to precision measurements, for example, to contrain the variation
of the fine-structure constant. The second project with a next-generation
hybrid atom--ion trap will ultimately allow precision work with ultra-cold
molecular ions.