High-threshold fault-tolerant quantum computation with analog quantum error correction

TL;DR

This paper proposes a fault-tolerant quantum computation scheme using GKP qubits with analog error correction and surface codes, significantly reducing the squeezing requirement from 14.8 dB to below 10 dB, making experimental realization more feasible.

Contribution

It introduces a novel method combining analog quantum error correction with topologically protected measurement-based quantum computation to lower the squeezing threshold needed for GKP qubits.

Findings

Squeezing requirement reduced from 14.8 dB to below 10 dB.

Analog information enhances error correction efficiency.

Method prevents squeezing degradation during large-scale cluster state construction.

Abstract

To implement fault-tolerant quantum computation with continuous variables, the Gottesman-Kitaev-Preskill (GKP) qubit has been recognized as an important technological element. However,it is still challenging to experimentally generate the GKP qubit with the required squeezing level, 14.8 dB, of the existing fault-tolerant quantum computation. To reduce this requirement, we propose a high-threshold fault-tolerant quantum computation with GKP qubits using topologically protected measurement-based quantum computation with the surface code. By harnessing analog information contained in the GKP qubits, we apply analog quantum error correction to the surface code.Furthermore, we develop a method to prevent the squeezing level from decreasing during the construction of the large scale cluster states for the topologically protected measurement based quantum computation. We numerically show that the required squeezing level can be relaxed to less than 10 dB, which is within the reach of the current experimental technology. Hence, this work can considerably alleviate this experimental requirement and take a step closer to the realization of large scale quantum computation.