We report the implementation of universal two-and three-qubit entangling gates on neutral atom qubits encoded in long-lived hyperfine ground states. The gates are mediated by excitation to strongly interacting Rydberg states, and are implemented in parallel on several clusters of atoms in a one-dimensional array of optical tweezers. Specifically, we realize the controlled-phase gate, enacted by a novel, fast protocol involving only global coupling of two qubits to Rydberg states. We benchmark this operation by preparing Bell states with fidelity F ≥ 95.0(2)%, and extract gate fidelity ≥ 97.4(3)%, averaged across five atom pairs. In addition, we report a proof-of-principle implementation of the three-qubit Toffoli gate, in which two control atoms simultaneously constrain the behavior of one target atom. These experiments demonstrate key ingredients for high-fidelity quantum information processing in a scalable neutral atom platform.

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The ability to engineer parallel, programmable operations between desired qubits within a quantum processor is key for building scalable quantum information systems1,2. In most state-of-the-art approaches, qubits interact locally, constrained by the connectivity associated with their fixed spatial layout. Here we demonstrate a quantum processor with dynamic, non-local connectivity, in which entangled qubits are coherently transported in a highly parallel manner across two spatial dimensions, between layers of single- and two-qubit operations. Our approach makes use of neutral atom arrays trapped and transported by optical tweezers; hyperfine states are used for robust quantum information storage, and excitation into Rydberg states is used for entanglement generation3–5. We use this architecture to realize programmable generation of entangled graph states, such as cluster states and a seven-qubit Steane code state6,7. Furthermore, we shuttle entangled ancilla arrays to realize a surface code state with thirteen data and six ancillary qubits8 and a toric code state on a torus with sixteen data and eight ancillary qubits9. Finally, we use this architecture to realize a hybrid analogue–digital evolution2 and use it for measuring entanglement entropy in quantum simulations10–12, experimentally observing non-monotonic entanglement dynamics associated with quantum many-body scars13,14. Realizing a long-standing goal, these results provide a route towards scalable quantum processing and enable applications ranging from simulation to metrology.

We describe the formation of fermionic NaLi Feshbach molecules from an ultracold mixture of bosonic 23 Na and fermionic 6 Li. Precise magnetic field sweeps across a narrow Feshbach resonance at 745 G result in a molecule conversion fraction of 5% for our experimental densities and temperatures, corresponding to a molecule number of 5 × 10 4 . The observed molecular decay lifetime is 1.3 ms after removing free Li and Na atoms from the trap. The preparation and control of ultracold atoms has led to major advances in precision measurements and many-body physics. One current frontier is to extend this to diatomic molecules. Early experiments focused on homonuclear molecules, where highlights included the study of fermion pairs across the BEC-BCS crossover [1]. The preparation of heteronuclear molecules is more challenging because it requires a controlled reaction between two distinct atomic species. However, heteronuclear molecules can have a strong elecric dipole moment, which leads to a range of new scientific directions [2], including precision measurements, such as of the electron electric dipole moment [3], quantum computation mediated by dipolar coupling between molecular qubits [4] or in a hybrid system of molecules coupled to superconducting waveguides [5], many-body physics with anisotropic long-range interactions [6,7], and ultracold chemistry [8].A number of experiments have explored molecule formation in ultracold atoms using photoassociation and Feshbach resonances [2].Due to the lower abundance of fermionic alkali isotopes, only one heteronuclear fermionic molecule 40 K 87 Rb has been produced at ultracold temperatures [9]. Fermionic molecules are appealing due to Pauli suppression of s-wave collisions between identical fermions [10], as well as prospects for preparing fermions with long-range interactions as a model system for electrons with Coulomb interactions [6]. In this paper, we report the formation of a new fermionic heteronuclear molecule 23 Na 6 Li.NaLi has at least three unique features due to its constituents being the two smallest alkali atoms. First, its small reduced mass gives it a large rotational constant, which suppresses inelastic molecule-molecule collisions that occur via coupling between rotational levels [11]. Second, NaLi is reactive in its singlet X 1 Σ + ground state, meaning that the reaction NaLi + NaLi → Na 2 + Li 2 is energetically allowed [12], but with an unusually small predicted rate constant of 10 −13 cm 3 /s that is by far the lowest among all reactive heteronuclear alkali molecules [13] and should allow lifetimes > 1 s even without dipolar suppression [14]. This is related to NaLi having the smallest van der Waals C 6 coefficient of all heteronuclear alkali atom pairs [15], which results in weak scattering by the long-range potential. Finally, this slow collision rate, together with weak spin-orbit coupling in diatomic molecules with small atomic numbers Z of its constituents [16], may allow a long-lived triplet a 3 Σ + ground-state in NaLi. This state has nonzero ...