Spin dephasing as a probe of mode temperature, motional state distributions, and heating rates in a two-dimensional ion crystal

Published

March 9, 2014

Author(s)

Brian C. Sawyer, Joseph W. Britton, John J. Bollinger

Abstract

We employ spin-dependent optical dipole forces to characterize the transverse center-of-mass (COM) motional mode of a two-dimensional trapped ion crystal of hundreds of ⁹Be⁺. By comparing the measured spin dephasing produced by the spin-dependent force with the predictions of a semiclassical dephasing model, we obtain absolute mode temperatures in excellent agreement with both the Doppler laser cooling limit and measurements obtained from a previously published technique (B. C. Sawyer et al. Phys. Rev. Lett. \textbf108}, 213003 (2012)). Furthermore, the structure of the dephasing histograms allows for discrimination between initial thermal and coherent states of motion. These measurements provide insight into the size and nature of errors in trapped ion quantum gates produced by thermal fluctuations of a motional mode. We also apply the techniques discussed here to measure, for the first time, the ambient heating rate of the COM mode of a 2D Coulomb crystal in a Penning trap. This measurement places an upper limit on the anomalous single-ion heating rate due to electric field noise from the trap electrode surfaces of $\sim 5$ s^-1} for our trap at a frequency of 795 kHz.

Citation

Physical Review A

Volume

89

Pub Type

Journals

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Keywords

non-neutral plasmas, quantum entanglement, transverse plasma modes

Citation

Sawyer, B. , Britton, J. and Bollinger, J. (2014), Spin dephasing as a probe of mode temperature, motional state distributions, and heating rates in a two-dimensional ion crystal, Physical Review A, [online], https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=915134 (Accessed December 3, 2024)