Patent ID: 8386899
Filing Date: 2013-02-26
Classification: B82Y,G06N,H03M,H04L

Abstract:
1. A quantum computing method comprising: operating a two-qubit gate on two qubits, the two-qubit gate having failure information related to success and failure (the failure information suggesting success is S, the failure information suggesting failure is F); when the failure information is F(S), defining failure information of the two qubits as F(S); executing an error-correction by an error-correcting teleportation, using a code to concatenate N-error-correcting code (N: an integral number equal to or larger than one) transversally executing Pauli gates, an Hadamard gate and a controlled-NOT gate (called a CNOT gate); executing the CNOT gate (called an encoded CNOT gate) to encoded qubits by error-correcting teleportations using |χ>≡|0000>+|0011>+|1101>+|1110>; when a measurement result of non-encoded qubits (called physical qubits, a gate of the physical qubit is called a physical gate) is processed (at level 0 (1=0), the encoded qubit is replaced with the physical qubit, and the encoded CNOT gate is replaced with a physical CNOT gate) in Bell measurement of the error-correcting teleportation, determining the measurement result and defining the failure information of the encoded qubit of each level by (1)˜(4), (1) when all of the encoded qubits of level l(1: an integral number equal to or larger than one) composing an encoded qubit of level (l+1) have failure information S, the measured value of the encoded qubit of level (l+1) is determined by N-error-correction, and failure information of the encoded qubit of level (l+1) is defined as S; (2) when the number of the encoded qubits of level l with failure information F composing an encoded qubit of level (l+1) is 1˜N, the measured value of the encoded qubit of level (l+1) is determined by N-error-correction and ignoring the failure information, and failure information of the encoded qubit of level (l+1) is defined as S; (3) when the number of the encoded qubits of level lwith failure information F composing an encoded qubit of level (l+1) is (N+1)˜2N; (3-1) when the syndrome as a 2N-erasure-error-correcting code represents no error or that only the qubits having failure information F have errors, the measured value of the encoded qubit of level (l+1) is determined by correcting the error, and failure information of the encoded qubit of level (l+1) is defined as S; (3-2) when the syndrome as a 2N-erasure-error-correcting code represents errors and that a qubit having failure information S has an error, the measured value of the encoded qubit of level (l+1) is determined by N-error-correction and ignoring the failure information, and failure information of the encoded qubit of level (l+1) is defined as F; (4) when the number of the encoded qubits of level l with failure information F composing an encoded qubit of level (l+1) is equal to or larger than (2N+1), the measured value of the encoded qubit of level (l+1) is determined by N-error-correction and ignoring the failure information, and failure information of the encoded qubit of level (l+1) is defined as F; wherein the measurement result of a logical qubit as the encoded qubit of the highest level is determined.