Search for: All records

Optically active defects in solid-state systems have many applications in quantum information and sensing. However, unlike free atoms, which have fixed optical transition frequencies, the inhomogeneous broadening of the transitions in solid-state environments limit their use as identical scatterers for such applications. Here we show that crystals of argon and neon prepared in a closed-cycle cryostat doped with thulium atoms at cryogenic temperatures are an exception. High resolution absorption and emission spectroscopy show that the 1140 nm magnetic dipole transition is split into multiple components. The origin of this splitting is likely a combination of different classes of trapping sites, crystal field effects within each site, and hyperfine interactions. The individual lines have ensemble widths as small as 0.6 GHz, which temperature dependence and pump-probe spectroscopy indicate is likely a homogeneous effect, suggesting inhomogeneity is well below the GHz scale. 

We place a molecular Bose-Einstein condensate in a 1D shaken lattice with a Floquet-engineered dispersion, and observe the dynamics in both position and momentum space. At the initial condition of zero momentum, our engineered dispersion is inverted, and therefore unstable. We observe that the condensate is destabilized by the lattice shaking as expected, but rather than decaying incoherently or producing jets, as in other unstable condensates, under our conditions the condensate bifurcates into two portions in momentum space, with each portion subsequently following semi-classical trajectories that suffer minimal spreading in momentum space as they evolve. We can model the evolution with a Gross-Pitaevskii equation, which suggests the initial bifurcation is facilitate by a nearly linear “inverted V”-shaped dispersion at the zone center, while the lack of spreading in momentum space is facilitated by interactions, as in a soliton. We propose that this relatively clean bifurcation in momentum space has applications for counter-diabatic preparation of exotic ground states in many-body quantum simulation schemes.