Method and device for quantum error filtering using quantum error filtering code

A quantum error filtering method of a computer device, the quantum error filtering method comprising:

• outputting, to a quantum circuit, a plurality of logical qubits each implemented as a plurality of physical qubits based on a predefined quantum error filtering code;
• detecting a quantum error in one of the input logical qubits based on parities measured from the physical qubits for the logical qubits input through the quantum circuit;
• and
• determining that a computational result from the quantum circuit is to be discarded based on the detected quantum error,
• wherein the quantum error filtering code includes a 2-qubit quantum error filtering code or a 4-qubit quantum error filtering code,
• wherein the 2-qubit quantum error filtering code is defined as two logical qubits as shown in the following equation,
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• where |0>L represents logical qubit of 0 qubit, |1>L represents logical qubit of 1 qubit, and + and − represent phases, and
• wherein the 4-qubit quantum error filtering code is defined as two logical qubits as shown in the following equation,
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• where |0>L represents logical qubit of 0 qubit, |1>L represents logical qubit of 1 qubit, 0 and 1 represent bits, and + and − represent phases.

A non-transitory computer-readable recording medium storing instructions that, when executed by a processor, cause the processor to perform a quantum error filtering method on a computer device, the quantum error filtering method comprising:

• outputting, to a quantum circuit, a plurality of logical qubits each implemented as a plurality of physical qubits based on a predefined quantum error filtering code;
• detecting a quantum error in one of the input logical qubits based on parities measured from the physical qubits for the logical qubits input through the quantum circuit;
• and
• determining that a computational result from the quantum circuit is to be discarded based on the detected quantum error,
• wherein the quantum error filtering code includes a 2-qubit quantum error filtering code or a 4-qubit quantum error filtering code,
• wherein the 2-qubit quantum error filtering code is defined as two logical qubits as shown in the following equation,
• ❘
• "\[LeftBracketingBar]"
• 0
• >
• L
• =
• ❘
• "\[LeftBracketingBar]"
• ++
• >
• ,
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• 1
• >
• L
• =
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• ‐
• ⁢
• ‐
• >
• where |0>L represents logical qubit of 0 qubit |1>L represents logical qubit of 1 qubit, and + and − represent phases, and
• wherein the 4-qubit quantum error filtering code is defined as two logical qubits as shown in the following equation,
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• 0
• >
• L
• =
• 1
• 2
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• (
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• >
• +
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• 11
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• +
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• 11
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• ,
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• 1
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• >
• -
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• 11
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• >
• -
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• where |0>L represents logical qubit of 0 qubit, |1>L represents logical qubit of 1 qubit, 0 and 1 represent bits, and + and − represent phases.