Raman sideband cooling of aBa+138ion using a Zeeman interval

Abstract

Motional ground state cooling and internal state preparation are important elements for quantum logic spectroscopy (QLS), a class of quantum information processing. Since QLS does not require the high gate fidelities usually associated with quantum computation and quantum simulation, it is possible to make simplifying choices in ion species and quantum protocols at the expense of some fidelity. Here, we report sideband cooling and motional state detection protocols for 138 Ba + of sufficient fidelity for QLS without an extremely narrowband laser or the use of a species with hyperfine structure. We use the two S 1/2 Zeeman sublevels of 138 Ba + to Raman sideband cool a single ion to the motional ground state. Because of the small Zeeman splitting, near-resonant Raman sideband cooling of 138 Ba + requires only the Doppler cooling lasers and two additional AOMs. Observing the near-resonant Raman optical pumping fluorescence, we estimate a final average motional quantum numbern ≈ 0.17. We additionally employ a second, far-off-resonant laser driving Raman π-pulses between the two Zeeman sublevels to provide motional state detection for QLS and to confirm the sideband cooling efficiency, measuring a finaln = 0.15(6).

Sideband Cooling of a Trapped Ion in Strong Sideband Coupling Regime

“…In the dressed state basis |± , the carrier transition vanishes as can be seen from Eq. (20), which is the same as the Hamiltonian considered in Ref. [46], while the dissipation in Eq.…”

“…Sideband cooling has been the method of choice to cool down a trapped ion into its motional ground state for a long time due to its simplicity and excellent performance in practice [14][15][16][17][18][19][20][21][22][23][24][25][26][27][28]. In its ideal settings, the standard sideband cooling only requires to couple the trapped ion to a single running wave laser, where the laser is able to excite the ion from a (meta-)stable ground state to an unstable excited state, and that the ion is pre-cooled into the Lamb-Dicke regime characterized by a small dimensionless Lamb-Dicke parameter η (η 1 means that the motion of the ion is negligible compared to the wave length of the laser, which could be achieved using some pre-cooling methods such as Doppler cooling [14] and polarization gradient cooling [29][30][31][32]).…”

Raman Sideband Cooling 171Yb+ Across Zeeman Sub-levels

“…2b). Simultaneous fits to the spectra and Rabi oscillations give thermal states with nx,y,z = [29 (2), 36(16), 16.2 (5)] and [0.07 (7), 2.0(1.2), 5.6(2)] before and after RSC respectively. Also fitted are the Raman transition Rabi rate 2π × 42.64(18) kHz and off-resonant scattering rate 2π × 1.36(4) kHz.…”

Towards an electrostatic storage ring for fundamental physics measurements

“…(iii) For polarization we plan to use a 650 nm laser and a 493 nm laser due to the metastable state [29]. The Zeeman splitting of the ground state in earth's magnetic field is 1 MHz, large enough to polarize the ions without further magnetic fields [30]. We plan on polarizing the ions directly in the ring for the final setup.…”