HARDWARE-EFFICIENT SYNDROME EXTRACTION FOR ENTANGLED QUANTUM STATES

摘要

A quantum-state-refresh module of a memory system is configured to detect an error in an entangled qubit state stored therein by performing a redundant measurement of syndrome values corresponding to a quantum stabilizer code, with the redundant measurement being based on a block error-correction code. The quantum-state-refresh module includes a plurality of measurement sub-modules, each configured to measure a respective syndrome value or a respective parity value corresponding to the entangled qubit state. The total number of the measurement sub-modules is smaller than the codeword length of the block error-correction code, and the initial approximation of the punctured syndrome values is replaced in the decoding process by erasure values. With the block error-correction code appropriately constructed for the use of erasure values, the quantum-state-refresh module is advantageously capable of providing reliable error detection with fewer quantum gates than that used for the full-length measurement of the codeword.

主权项

1. An apparatus comprising:
a register configured to store a coded entangled qubit state generated using a quantum stabilizer code; a measurement circuit configured to perform a redundant measurement of a set of syndrome values corresponding to the coded entangled qubit state, wherein the redundant measurement is performed based on a block error-correction code; an erasure-value generator configured to generate a set of erasure values; and a decoder configured to determine a probable syndrome vector corresponding to the coded entangled qubit state using the block error-correction code and the redundant measurement of the set of syndrome values, and further configured to apply the set of erasure values generated by the erasure-value generator to a set of variable nodes not configured to receive a measured syndrome value from the measurement circuit.