A framework for low-overhead quantum fault tolerance via spacetime lifting

Abstract:Fault-tolerant quantum computation is inherently a spacetime problem, requiring not merely good static quantum error-correcting codes but also low-overhead protocols for protecting and manipulating encoded quantum information over time. Fault complexes provide a homological framework for treating such protocols as single spacetime objects. In this work, we initiate the study of low-overhead fault complexes by introducing {spacetime lifting}, a method that constructs fault complexes from symmetry-reduced product structures beyond standard foliation. We show that spacetime lifting yields fault complexes and in particular {spacetime-lifted} memory experiments with almost-linear fault distance in the total spacetime cost, which substantially outperforms existing constructions. We further interpret fault complexes as measurement-based cluster-state protocols and identify general conditions under which they realize fault-tolerant logical teleportation, showing that spacetime-lifted constructions combine favorable scaling with operational schemes. Our study opens a path toward more efficient quantum fault tolerance through general complex constructions.

arXiv:2606.06365 [quant-ph]

(or arXiv:2606.06365v1 [quant-ph] for this version)

https://doi.org/10.48550/arXiv.2606.06365 Focus to learn more arXiv-issued DOI via DataCite (pending registration)

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