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Quantum logic and precision measurements with atomic and molecular ions

November 8, 2018 - 11:00am
David Leibrandt
NIST Boulder & University of Colorado

The tools of trapped-ion quantum logic can be used to enable and
enhance precision measurements.  In this seminar, I will present NIST
Ion Storage Group experiments at this fertile intersection of fields.
I will begin with a review of optical atomic clocks based on Al+,
which use quantum logic with a second ion species for preparation and
readout of the Al+ state.  Recent progress, including an improved ion
trap design and laser cooling to the 3D ground state, has enabled
total fractional systematic uncertainty below 10^-18.  We have
performed frequency ratio measurements between our Al+ clocks and the
NIST/JILA optical lattice clocks, which can be used to place
constraints on models of ultralight bosonic dark matter.  I will next
describe ideas for reaching the Heisenberg stability limit for
frequency ratio measurements involving clocks based on multiple,
entangled Al+ ions.  Finally, I will summarize an experiment in which
quantum-logic readout is used to projectively prepare pure rotational
and hyperfine states of CaH+.  By directly driving coherent Raman
transitions with a frequency comb, the THz frequencies of rotational
transitions are characterized with sub 100 Hz resolution, and
entangled states between Ca+ and CaH+ are produced.

PSC 3150