Engineering controllable, strongly interacting many-body quantum systems is at the frontier of quantum simulation and quantum information processing. Arrays of laser-cooled neutral atoms in optical tweezers have emerged as a promising platform, because of their flexibility and the potential for strong interactions via Rydberg states. Existing neutral atom array experiments utilize alkali atoms, but alkaline-earth atoms offer many advantages in terms of coherence and control, and also open the door to new applications in precision measurement and timekeeping. In this work, we present a technique to trap individual alkaline-earth-like Ytterbium (Yb) atoms in optical tweezer arrays. The narrow 1 S0 -3 P1 intercombination line is used for both cooling and imaging in a magicwavelength optical tweezer at 532 nm. The low Doppler temperature allows for imaging near the saturation intensity, resulting in a very high atom detection fidelity. We demonstrate the imaging fidelity concretely by observing rare (< 1 in 10 4 images) spontaneous quantum jumps into and out of a metastable state. We also demonstrate stochastic loading of atoms into a two-dimensional, 144site tweezer array. This platform will enable advances in quantum information processing, quantum simulation and precision measurement. The demonstrated narrow-line Doppler imaging may also be applied in tweezer arrays or quantum gas microscopes using other atoms with similar transitions, such as Erbium and Dysprosium.Neutral atom arrays are an emerging platform for quantum simulation and quantum information processing. The use of individual optical tweezers [1] to trap atoms offers unprecedented control for bottom-up assembly of large-scale quantum systems, while interactions and entanglement can be realized through collisions [2], Rydberg states [2-8], optical cavities [9] or the formation of molecules [10]. Crucially, the entropy associated with stochastic loading from a magneto-optical trap can be eliminated using rapid imaging, feedback and rearrangement of the atoms' positions [11], allowing for uniform filling of large 1D [12], 2D [13,14] and 3D [15,16] arrays. In recent years, these systems have been used to probe many-body quantum dynamics [7, 8] engineer multi-qubit gates, and prepare entangled states [2,[4][5][6].All experiments to date involving optical tweezers have utilized alkali atoms, in particular Rb [1,2,4,[12][13][14]16], Cs [6,10,17] and Na [10,17]. However, alkaline earth atoms offer several intriguing advantages [18] including ultra-long coherence for nuclear spins in the J = 0 electronic ground state, a combination of strong and narrow optical transitions for rapid laser cooling to very low temperatures, and metastable shelving states to facilitate high-fidelity qubit readout. Interaction between nuclear spin qubits can be realized using Rydberg states (which feature strong hyperfine coupling in alkaline earth atoms [19,20]) or coherent spin-exchange collisions using the metastable clock state [21][22][23][24]. Furthermore, Rydberg states may...

We present a map of the near subsurface hydrogen distribution on Mars, based on epithermal neutron data from the Mars Odyssey Neutron Spectrometer. The map's spatial resolution is approximately improved two-fold via a new form of the pixon image reconstruction technique. We discover hydrogen-rich mineralogy far from the poles, including ∼10 wt. % water equivalent hydrogen (WEH) on the flanks of the Tharsis Montes and >40 wt. % WEH at the Medusae Fossae Formation (MFF). The high WEH abundance at the MFF implies the presence of bulk water ice. This supports the hypothesis of recent periods of high orbital obliquity during which water ice was stable on the surface. We find the young undivided channel system material in southern Elysium Planitia to be distinct from its surroundings and exceptionally dry; there is no evidence of hydration at the location in Elysium Planitia suggested to contain a buried water ice sea. Finally, we find that the sites of recurring slope lineae (RSL) do not correlate with subsurface hydration. This implies that RSL are not fed by large, near-subsurface aquifers, but are instead the result of either small (<120 km diameter) aquifers, deliquescence of perchlorate and chlorate salts or dry, granular flows.

Neutral atom qubits with Rydberg-mediated interactions are a leading platform for developing large-scale coherent quantum systems. In the majority of experiments to date, the Rydberg states are not trapped by the same potential that confines ground state atoms, resulting in atom loss and constraints on the achievable interaction time. In this work, we demonstrate that the Rydberg states of an alkaline earth atom, ytterbium, can be stably trapped by the same red-detuned optical tweezer that also confines the ground state, by leveraging the polarizability of the Yb + ion core. Using the previously unobserved 3 S1 series, we demonstrate trapped Rydberg atom lifetimes exceeding 100 µs, and observe no evidence of auto-or photo-ionization from the trap light for these states. We measure a coherence time of T2 = 59 µs between two Rydberg levels, exceeding the 28 µs lifetime of untrapped Rydberg atoms under the same conditions. These results are promising for extending the interaction time of Rydberg atom arrays for quantum simulation and computing, and are vital to capitalize on the extended Rydberg lifetimes in circular states or cryogenic environments.

the Moon, using data from the Lunar Prospector Gamma Ray Spectrometer. We enhance the resolution via a pixon image reconstruction technique and find that the thorium is distributed over a larger (40 km × 75 km) area than the (25 km × 35 km) high-albedo region normally associated with Compton-Belkovich. Our reconstructions show that inside this region, the thorium concentration is 14-26 ppm. We also find additional thorium, spread up to 300 km eastward of the complex at ∼ 2 ppm. The thorium must have been deposited during the formation of the volcanic complex, because subsequent lateral transport mechanisms, such as small impacts, are unable to move sufficient material. The morphology of the feature is consistent with pyroclastic dispersal, and we conclude that the present distribution of thorium was likely created by the explosive eruption of silicic magma.