Efficient Assembly of a Defect-Free Quantum Register of 1024 Neutral-Atom Qubits

This paper presents a significant advancement in neutral-atom quantum information science by scaling the assembly of defect-free quantum registers to the kiloqubit level. The researchers utilize a modular microoptical architecture that separates the generation of the tweezer array from the spatial shaping of the laser intensity. This decoupling allows for the creation of highly uniform, large-scale arrays of optical tweezers, which are essential for maintaining consistent trap depths and vibrational frequencies across the entire register.

The core of the experimental setup involves two interleaved microlens arrays (MLAs) illuminated by homogenized top-hat laser profiles. This configuration generates more than 3500 trap sites. To assemble a defect-free quantum processing unit (QPU), the authors employ a parallelized, acousto-optic deflector (AOD)-based transport system. This system allows for the rapid, real-time relocation of individual atoms from a reservoir array into a target pattern. By implementing a greedy nearest-assignment algorithm, the researchers can efficiently move multiple atoms simultaneously, significantly reducing the time required for array assembly compared to single-tweezer transport methods.

The authors successfully demonstrate the assembly of a 32x32 site QPU containing 1024 defect-free atomic qubits. The system achieves a near-unity filling fraction of 99.3(2)%. The parallelized transport mechanism provides a speedup factor of approximately 9 for the 1024-atom target structure compared to sequential transport. The uniformity of the trap array, characterized by the radial vibrational frequency, shows a root-mean-square deviation of 4.5% across the 32x32 site region, which is a substantial improvement over standard Gaussian-illuminated arrays.