Physicists in China have demonstrated that a structure called an optical metasurface can individually trap up to 78,400 neutral atoms – a promising development in efforts to build a large-scale quantum computer. The method, which is similar to one demonstrated independently by a team at Columbia University in the US, could help overcome a troublesome bottleneck for computers that use neutral atoms as their quantum bits (qubits). Arrays of trapped neutral atoms are widely employed in physics research, and they are a promising platform for quantum computing. Their main drawback is scalability, explains physicist Zhongchi Zhang, who co-led the new study together with his Tsinghua University colleague Xue Feng. The components normally used to make such arrays, such as spatial light modulators (SLMs) and acousto-optic deflectors (AODs), can only create around 10,000 atom traps at any one time, and are thus limited to a maximum of 10,000 atomic qubits.…