Optical stimulated-Raman sideband spectroscopy of a single $^9$Be$^+$ ion in a Penning trap

TL;DR

This paper demonstrates optical stimulated-Raman spectroscopy of a single $^9$Be$^+$ ion in a cryogenic Penning trap, measuring motional sidebands and effective mode temperature, advancing quantum logic in Penning traps for fundamental physics tests.

Contribution

It introduces a method for high-precision Raman spectroscopy of a single ion in a Penning trap, enabling quantum logic operations and precision measurements.

Findings

Measured Raman resonances with and without motional sidebands

Determined an effective mode temperature of 3.1 mK

Established a technique for quantum logic in Penning traps

Abstract

We demonstrate optical sideband spectroscopy of a single $^9$Be$^+$ ion in a cryogenic 5 Tesla Penning trap using two-photon stimulated-Raman transitions between the two Zeeman sublevels of the $1s^{2}2s$ ground state manifold. By applying two complementary coupling schemes, we accurately measure Raman resonances with and without contributions from motional sidebands. From the latter we obtain an axial sideband spectrum with an effective mode temperature of (3.1 $\pm$ 0.4)~mK. This results are a key step for quantum logic operations in Pennings traps, applicable to high precision matter-antimatter comparisons tests in the baryonic sector of the standard model.