Narrow-Line Cooling and Imaging of Ytterbium Atoms in an Optical Tweezer Array

Abstract

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...

Quantum non-demolition measurement of a many-body Hamiltonian

“…The present work outlines an ion-trap implementation with COM phonons as meter. However, the concepts and techniques carry over to other platforms including CQED with atoms [47] and superconducting qubits [48], where the role of the meter can be represented by cavity photons read with homodyne detection, and Rydberg tweezer arrays [8][9][10][11][12] by coupling to a small atomic ensemble encoding the continuous meter variables [49], respectively. Finally, while the present work considers QND measurement of the total HamiltonianĤ of an isolated system, our approach generalizes to measuring HamiltoniansĤ A of subsystems, as is of interested in quantum transport of energy, or energy exchange in coupling the many-body system of interest to a bath.…”

Many-body physics with individually controlled Rydberg atoms

“…The second short-term prospect is the extension of the techniques that have so far been applied to alkali atoms to new atomic species with two valence electrons. Arrays of single Strontium [102][103][104] and Ytterbium [105] atoms have been reported recently. Although so far no quantum simulation has been performed with these novel systems, the richer internal structure of these species might allow new ways to manipulate, control and probe them [106,107].…”

Practical designs for permutation-symmetric problem Hamiltonians on hypercubes

“…While there are many potential platforms which could be used to implement the necessary interactions, we have chosen Rydberg atoms [48,49] as they are one of the few platforms for quantum information processing that offer the flexibility of fully 3D geometries [50]. Although fidelity is lower than other systems, such as ions and superconducting qubits, recently there has been rapid progress in, for example, entanglement protocols [51,52] and creating optical tweezer arrays using species such as strontium [53,54] and ytterbium [55]. Particularly attractive for the encoding scheme proposed here, is the possibility of all-to-all connectivity in 3D, the ability to exploit the angular dependence of the dipole-dipole couplings [48,50].…”