Quantum processing architectures that include multiple qubit modalities offer compelling strategies for high-fidelity operations and readout, quantum error correction, and a path for scaling to large system sizes.Such hybrid architectures have been realized for leading platforms, including superconducting circuits and trapped ions.Recently, a new approach for constructing large, coherent quantum processors has emerged based on arrays of individually trapped neutral atoms.However, these demonstrations have been limited to arrays of a single atomic element where the identical nature of the atoms makes crosstalk-free control and nondemolition readout of a large number of atomic qubits challenging.Here we introduce a dual-element atom array with individual control of single rubidium and cesium atoms.We demonstrate their independent placement in arrays with up to 512 trapping sites and observe negligible crosstalk between the two elements.Furthermore, by continuously reloading one atomic element while maintaining an array of the other, we demonstrate a new continuous operation mode for atom arrays without any off-time.Our results enable avenues for auxiliary-qubit-assisted quantum protocols such as quantum nondemolition measurements and quantum error correction, as well as continuously operating quantum processors and sensors.
Quantum processing architectures that include multiple qubit modalities offer compelling strategies for high-fidelity operations and readout, quantum error correction, and a path for scaling to large system sizes.Such hybrid architectures have been realized for leading platforms, including superconducting circuits and trapped ions.Recently, a new approach for constructing large, coherent quantum processors has emerged based on arrays of individually trapped neutral atoms.However, these demonstrations have been limited to arrays of a single atomic element where the identical nature of the atoms makes crosstalk-free control and nondemolition readout of a large number of atomic qubits challenging.Here we introduce a dual-element atom array with individual control of single rubidium and cesium atoms.We demonstrate their independent placement in arrays with up to 512 trapping sites and observe negligible crosstalk between the two elements.Furthermore, by continuously reloading one atomic element while maintaining an array of the other, we demonstrate a new continuous operation mode for atom arrays without any off-time.Our results enable avenues for auxiliary-qubit-assisted quantum protocols such as quantum nondemolition measurements and quantum error correction, as well as continuously operating quantum processors and sensors.
Neutral-atom arrays are a leading platform for quantum technologies, offering a promising route toward large-scale, fault-tolerant quantum computing. We propose a novel quantum processing architecture based on dual-type, dual-element atom arrays, where individually trapped atoms serve as data qubits, and small atomic ensembles enable ancillary operations. By leveraging the selective initialization, coherent control, and collective optical response of atomic ensembles, we demonstrate ensemble-assisted quantum operations that enable reconfigurable, high-speed control of individual data qubits and rapid mid-circuit readout, including both projective single-qubit and joint multi-qubit measurements. The hybrid approach of this architecture combines the long coherence times of single-atom qubits with the enhanced controllability of atomic ensembles, achieving high-fidelity state manipulation and detection with minimal crosstalk. Numerical simulations indicate that our scheme supports individually addressable single- and multi-qubit operations with fidelities of 99.5% and 99.9%, respectively, as well as fast single- and multi-qubit state readout with fidelities exceeding 99% within tens of microseconds. These capabilities open new pathways toward scalable, fault-tolerant quantum computation, enabling repetitive error syndrome detection and efficient generation of long-range entangled many-body states, thereby expanding the quantum information toolbox beyond existing platforms.
Over the past decade, quantum information science has progressed from few-qubit demonstrations to experiments with hundreds of qubits. Neutral atom processors based on individual atoms trapped in arrays of optical tweezers have emerged as a leading candidate due to their inherent scalability and flexible connectivity. Advanced protocols like measurement-based state preparation and quantum error correction, however, require efficient crosstalk-free mid-circuit operations for the readout, reset, and replenishment of a subset of qubits. In typical single-species atom arrays, where all atoms are identical and on-resonance, such operations necessitate complex overheads from single-site addressing, coherent transport, or shielding techniques, to mitigate the qubit decoherence induced from photons scattered by neighboring atoms. To address this challenge of engineering scalable quantum architectures compatible with efficient control techniques, we introduce and implement the first dual-species atom array platform, and explore new dynamics inaccessible in single-species arrays. In this approach, two atomic species are addressed independently due to the spectral separation between their control wavelengths. We engineer two-dimensional arrays from individual rubidium (Rb) and cesium (Cs) atoms in up to 512 optical tweezers, and show that the two species can be independently trapped, cooled, and imaged with state-of-the-art performance metrics. Harnessing this intrinsic crosstalk-free control, we establish the key primitives of mid-circuit readout, real-time processing and feed-forward, and coherent mid-circuit reloading. By integrating these capabilities, we realize in-sequence, real-time correction of correlated phase errors via a spectator qubit protocol. Next, we excite atoms to Rydberg states in the Förster regime, accessing hitherto unobserved enhanced interspecies Rydberg interactions, and program them to implement the first interspecies CNOT gate. We combine this multispecies entanglement with mid-circuit readout to achieve quantum non-demolition measurement of a Rb-qubit using an auxiliary Cs-qubit, circumventing physical qubit transport. Finally, leveraging the two qubit modalities, we present the first experimental demonstration of quantum cellular automata in atom arrays using only global addressing, and prepare a 17-qubit Cs cluster state with Rb-mediated interactions. The dual-species platform and techniques established in this thesis pave the way toward measurement-based algorithms and real-time feedback control in large-scale quantum systems.
Neutral atom arrays have emerged as a leading platform for scalable quantum information processing, offering reconfigurable geometry, strong interactions, and high-fidelity control. While encoding quantum information in atomic qubits provides multiple natural advantages, information can be lost through mechanisms such as atom loss, depolarization, and decoherence, necessitating the need for quantum error correction. However, the processes underlying error correction, including measurement and gate operations, can themselves induce atom loss, ultimately limiting the achievable computational circuit depth. This thesis presents the design and realization of a large-scale neutral atom array quantum architecture capable of continuous coherent operation. By replenishing fresh atomic qubits during operation, the system solves a key bottleneck to scalability in space and time. We further show that, through careful system design, quantum coherence can be preserved while introducing new atoms and initializing them as qubits. We discuss the architectural and physical considerations underlying this approach and demonstrate a platform comprising more than 3,000 reconfigurable qubits. These results establish a pathway toward persistent quantum operation and have broad implications for quantum computing, quantum simulation, and quantum metrology.
Neutral atoms are a promising platform for quantum science, enabling advances in areas ranging from quantum simulations 1−3 and computation 4−10 to metrology, atomic clocks 11−13 and quantum networking 14−16 . While atom losses typically limit these systems to a pulsed mode, continuous operation 17−22 could significantly enhance cycle rates, remove bottlenecks in metrology 23 , and enable deep-circuit quantum evolution through quantum error correction 24,25 . Here we demonstrate an experimental architecture for high-rate reloading and continuous operation of a large-scale atom array system while realizing coherent storage and manipulation of quantum information. Our approach utilizes a series of two optical lattice conveyor belts to transport atom reservoirs into the science region, where atoms are repeatedly extracted into optical tweezers without affecting the coherence of qubits stored nearby. Using a reloading rate of 300,000 atoms in tweezers per second, we create over 30,000 initialized qubits per second, which we leverage to assemble and maintain an array of over 3,000 atoms for more than two hours. Furthermore, we demonstrate persistent refilling of the array with atomic qubits in either a spin-polarized or a coherent superposition state while preserving the quantum state of stored qubits. Our results pave the way for realization of large-scale continuously operated atomic clocks, sensors, and fault-tolerant quantum computers.
Arrays of single atoms trapped in optical tweezers are increasingly recognized as a promising platform for scalable quantum computing. In both the fault-tolerant and NISQ eras, the ability to individually control qubits is essential for the efficient execution of quantum circuits. Time-division multiplexed control schemes based on atom shuttling or beam scanning have been employed to build programmable neutral atom quantum processors, but achieving high-rate, highly parallel gate operations remains a challenge. Here, we propose a fiber array architecture for atom quantum computing capable of fully independent control of individual atoms. The trapping and addressing lasers for each individual atom are emitted from the same optical waveguide, enabling robust control through common-mode suppression of beam pointing noise. Using a fiber array, we experimentally demonstrate the trapping and independent control of ten single atoms in two-dimensional optical tweezers, achieving individually addressed single-qubit gates with an average fidelity of 0.9966(3). More significantly, we perform simultaneous arbitrary single-qubit gates on four randomly selected qubits, resulting in an average fidelity of 0.9961(4). Our work paves the way for time-efficient execution of quantum algorithms on neutral atom quantum computers.
Quantum computers hold a promise to solve certain problems that are intractable to classical computers, offering a paradigm shift in fields ranging from cryptography to materials science. However, realizing this potential requires overcoming the challenge of scalability, which encompasses both spatial scalability – the capacity for large qubit registers, and temporal scalability – the capability to execute deep quantum circuits. This thesis describes the construction and experimental characterization of a new rubidium atom array quantum platform, which advances the scalability frontier of atomic quantum processors in both spatial and temporal domains. The platform achieves a record-scale ∼ 99%-filling-fraction array with more than 3,000 qubits, and is shown to operate continuously for more than 2 hours. These advances are enabled by a novel architecture that supports high-flux refilling of atomic qubits without decohering neighboring sites. Combined with other recent progress demonstrated in the field of neutral atom quantum information processing, this platform provides a viable pathway toward large-scale, fault-tolerant quantum processing capable of executing deep error-corrected circuits.