Measurement-free Preparation of Surface-Code States with Digital-Analog Counterdiabatic Drivings

Abstract:Preparing stabilizer-code states with shallow circuits is an important primitive for near-term quantum error correction in superconducting circuits, where logical-state initialization requires four-body stabilizer correlations from native one- and two-body controls. We introduce a digital-analog method for the preparation of surface-code ground-state manifolds. The method exploits a structural property of the adiabatic gauge potential, mapping stabilizer-local counterdiabatic terms to digital-analog blocks on the superconducting layout using fixed-angle two-qubit \(XY\) gates, single-qubit rotations, and analog exchange-interaction evolutions. The dressed blocks generate higher-order operators used as the variational ansatz to determine the counterdiabatic terms within the Sels-Polkovnikov adiabatic-gauge-potential framework. We benchmark checkerboard plaquette-stabilizer grids up to \(4\times4\), the square-grid instances correspond to rotated surface codes, while the rectangular cases probe the scaling of the method. For all grids, the proposed method generates the dominant four-body counterdiabatic basis and, at short evolution times substantially improves the ground-state preparation as compared with bare adiabatic evolution. We further generalize the construction to \(n\times m\) stabilizer lattices and show that digital-analog synthesis can reduce the entangling depth by an order of magnitude. Together, these results establish a direct connection between stabilizer geometry, the structure of the counterdiabatic gauge potential, and digital-analog control for measurement-free preparation of stabilizer-code states on near-term superconducting architecture.

arXiv:2610.06697 [quant-ph]

(or arXiv:2610.06697v1 [quant-ph] for this version)

https://doi.org/10.48550/arXiv.2610.06697 Focus to learn more arXiv-issued DOI via DataCite (pending registration)

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