US 12,406,201 B2
Magic state injection into surface codes using hook error mechanisms
Craig Gidney, Goleta, CA (US)
Assigned to Google LLC, Mountain View, CA (US)
Filed by Google LLC, Mountain View, CA (US)
Filed on Feb. 16, 2024, as Appl. No. 18/444,147.
Claims priority of provisional application 63/485,420, filed on Feb. 16, 2023.
Prior Publication US 2025/0005423 A1, Jan. 2, 2025
Int. Cl. G06N 10/70 (2022.01); G06N 10/20 (2022.01); G06N 10/40 (2022.01)
CPC G06N 10/70 (2022.01) [G06N 10/20 (2022.01); G06N 10/40 (2022.01)] 20 Claims
OG exemplary drawing
 
1. A method implemented by a quantum computer for encoding a magic state in a surface code patch of physical qubits with a target distance, the method comprising:
performing a first surface code cycle on a surface code patch of physical qubits with an initial distance to encode the magic state into the surface code patch of physical qubits, wherein
performing the first surface code cycle introduces a hook error associated with a four-body stabilizer on a qubit included in the surface code patch, wherein the hook error rotates a logical observable of the surface code patch, and
performing the first surface code cycle comprises initializing the qubit in the magic state;
performing one or more rounds of error detection on the surface code patch of physical qubits that encodes the magic state; and
expanding the surface code patch of physical qubits to the target distance based on results of the one or more rounds of error detection.