A robust phase of continuous transversal gates in quantum stabilizer codes
ORAL
Abstract
A quantum error correcting code protects encoded logical information against errors. Transversal gates are a naturally fault-tolerant way to manipulate logical qubits but cannot be universal themselves. Protocols such as magic state distillation are needed to achieve universality via measurements and postselection. A phase is a region of parameter space with smoothly varying large-scale statistical properties except at its boundaries. Here, we find a phase of continuously tunable logical unitaries for the surface code implemented by transversal operations and decoding that is robust against dephasing errors. The logical unitaries in this phase have an infidelity that is exponentially suppressed in the code distance compared to their rotation angles. We exploit this to design a simple fault-tolerant protocol for continuous-angle logical rotations. This lowers the overhead for applications requiring many small-angle rotations such as quantum simulation.
*E.H. and M.J.G acknowledge support from Defense Advanced Research Projects Agency (DARPA) under Agreement No. HR00112490357 and NSF QLCI award no. OMA2120757. S.G. was supported through the Co-design Center for Quantum Advantage (C2QA) under contract number DE-SC0012704. P.R. acknowledges funding support from NSERC, FRQNT and INTRIQ. EH is supported by the Fulbright Future Scholarship. This work was performed in part at the Kavli Institute for Theoretical Physics (KITP), which is supported by grant NSF PHY-2309135.
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Publication: E. Huang, P. Rozon, A. Dua, S. Gopalakrishnan, M.J. Gullans, A robust phase of continuous transversal gates in quantum stabilizer codes (2025), arxiv:2510.01319 [quant-ph]
Presenters
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Eric Huang
- University of Maryland College Park and QuEra Computing Inc.
- University of Maryland College Park