Abstract Dipolar ultracold gases are of great interest for quantum simulation experiments. The first step of such a simulation is deep cooling of atoms in a pre-specified internal state. The results of detailed studies of the formation of a spin-polarized cloud of thulium atoms in a dipole trap are presented. We have calibrated the magnetic field by means of radio-frequency Zeeman spectroscopy and measured the polarization of atoms in an optimized trap by the beam expansion method in a magnetic field gradient based on this calibration. We have obtained 1.1 × 106 atoms at a temperature of 27 μK with polarization 〈mF〉 = –3.95 ± 0.12.
Characterization of the trap rf induced a.c. Zeeman shift is essential for achieving high accuracy in optical ion clocks. In this work, we demonstrate the experimental characterization of this shift using highly charged
Ca14+. The transverse component of the a.c. magnetic field is measured using the Autler-Townes splitting of the equally-spaced Zeeman components of the
3P1 when the Zeeman splitting is close to resonance with the trap rf drive frequency. We observe the resulting modulation by performing quantum logic spectroscopy using the co-trapped
Be+. The longitudinal component is measured from probing the
Be+ magnetic field-insensitive hyperfine transition
∣F=2,mF=0⟩→∣F=1,mF=0⟩. We confirm the small influence of the a.c. Zeeman shift in highly charged ions. The employed techniques can easily be transferred to other multi-level atomic systems.
We perform two-dimensional Fourier transform spectroscopy on magneto-excitons in GaAs at magnetic fields and observe Zeeman splitting of the excitons. The Zeeman components are clearly resolved as separate peaks due to the two-dimensional nature of the spectra, leading to a more accurate measurement of the Zeeman splitting and the Landé g factors. Quantum coherent coupling between Zeeman components is observed using polarization dependent one-quantum two-dimensional spectroscopy. We use two-quantum two-dimensional spectroscopy to investigate higher four-particle correlations at high magnetic fields and reveal the role of the Zeeman splitting on the two-quantum transitions. The experimental two-dimensional spectra are simulated using the optical Bloch equations, where many-body effects are included phenomenologically.