Constructing fault complexes for quantum error correction was previously limited by a square-root scaling barrier in relation to the resources needed. Yijia Xu of the University of Maryland, and colleagues from Shanghai Institute for Mathematics and Interdisciplinary Sciences (SIMIS) and Tsinghua University have introduced “spacetime lifting”, a new method for building these complexes that sharply outperforms existing constructions. The approach achieves fault complexes with almost-linear fault distance in total spacetime cost, representing a key step towards more efficient quantum computation and improved fault tolerance. Yijia Xu and colleagues have devised a new technique, termed “spacetime lifting”, to construct more efficient quantum error correction systems. The method moves beyond traditional approaches by considering both the spatial arrangement and timing of error correction processes as a single, unified system. Consequently, this yields fault complexes, the building blocks of error correction, with sharply reduced resource requirements compared to previous designs. Yijia Xu and colleagues are pioneering a new approach to quantum error correction, addressing a vital limitation in building practical quantum computers. Creating the necessary “fault complexes”, a way of visualising quantum error correction as a four-dimensional object, has been hampered by a scaling issue where the resources required increased disproportionately to the complexity of the correction. This new technique, called “spacetime lifting”, considers both the spatial arrangement and timing of error correction as a unified system, yielding fault complexes with sharply reduced resource demands. The innovation achieves almost-linear fault distance, the amount of error a quantum system can withstand before losing information, in relation to the total spacetime cost. Almost-linear fault distance scaling enabled by spacetime lifting Spacetime lifting achieves a fault distance scaling that is almost-linear in total spacetime cost, a substantial improvement over existing constructions limited by square-root scaling. This breakthrough crosses a key threshold in quantum error correction, where