Toward Fault-Tolerant Logical Qubits in a Three-Dimensional Neutral-Atom Array

Recent demonstrations of thousands of physical qubits and implementations of encoded logical qubits position neutral atom arrays as a leading platform for utility-scale quantum computation. Nonetheless, practical quantum advantage requires millions of physical qubits, demanding substantial advances in optical power delivery and real-time control. A key challenge in scaling optical tweezer arrays is that, in conventional two-dimensional (2D) architectures, the required optical power for trapping grows proportionally with the number of traps. To address this bottleneck, we are developing a three-dimensional (3D) neutral-atom array that reuses optical power across multiple axial planes, improving power efficiency per site and enabling geometrical flexibility for quantum error correction (QEC). We report our progress toward fault-tolerant 3D logical qubits. We explore 3D tweezer geometries that are optimized for implementing high-rate qLDPC codes (e.g., bivariate bicycle codes). In parallel, we are implementing single-shot multi layer read out, fast 3D tweezer reconfiguration, and advanced laser-cooling methods to rapidly prepare deterministic 3D arrays.