Ion-based precision measurements research has been growing rapidly in recent years, due to the improvement and discovery of spectroscopic methods, new possible uses and the introduction of new ions as frequency probes. Simultaneously, the search for a quantum computing platform with operations in superb fidelity have led to the development of tools aimed at keeping coherence of quantum systems on long time scales.
In my talk, I will review five experiments done in our group in which we used tools from quantum information – dynamical decoupling (DD) and decoherence-free subspaces – in precision measurements, allowing for an increase in precision as well as a reduction in noise.
First, I will describe an experiment in which we employed entanglement between ions to perform a close-to-Heisenberg-limited Rabi spectroscopy measurement on two ions , measuring both their clock transition frequency and, using a two-ion decoherence free-subspace, their difference in frequency. In a second experiment, utilizing the notion of DD, we used the ion as a force detector for AC forces at a frequency much lower than the ion’s trapping frequency . In another set of experiments, we employed a radio-frequency (RF) DD of spin >1/2 in order to measure the quadrupole moment of the 5D1/2 level in 88Sr+ – a physical quantity related to an important optical clock systematic shift – to the best precision to date . We used the same RF tool for spin > 1/2 to cancel the quadrupole shift on the clock transition of 88Sr+ . In collaboration with several other theoretical and experimental groups, my group also proposed another DD scheme to measure Lorentz invariance violation in the electron sector, with potential applicability to many physical systems, including trapped ions, highly-charged ions and neutral atoms .
 “Toward Heisenberg-Limited Rabi Spectroscopy,” Ravid Shaniv, Tom Manovitz, Yotam Shapira, Nitzan Akerman and Roee Ozeri, Phys. Rev. Lett. 120, 243603 (2018).
 “Quantum Lock-in Force Sensing Using Optical Clock Doppler Velocimetry,” Ravid Shaniv and Roee Ozeri. Nature Communications, 8 (2017): ncomms14157.
 “Atomic Quadrupole Moment Measurement Using Dynamic Decoupling,” Ravid Shaniv, Nitzan Akerman and Roee Ozeri, Phys. Rev. Lett. 116, 140801 (2016).
 “Quadrupole shift cancellation using dynamic decoupling,” Ravid Shaniv, Nitzan Akerman, Tom Manovitz, Yotam Shapira and Roee, arXiv:1808.10727 (2018).
 “New ideas for tests of Lorentz invariance with atomic systems,” Ravid Shaniv, Roee Ozeri, Marianna S. Safronova, Sergey G. Porsev, Vladimir A. Dzuba, Victor V. Flambaum and Hartmut Haeffner, Phys. Rev. Lett. 120, 103202 (2018).
Host: Jack Harris