QECOOL: On-Line Quantum Error Correction with a Superconducting Decoder for Surface Code

TL;DR

This paper introduces an online quantum error correction algorithm and superconducting hardware implementation that efficiently detects and corrects errors in surface code quantum computers, achieving high speed and low power consumption.

Contribution

It presents a novel online QEC algorithm and its superconducting hardware design, optimized for power efficiency and decoding speed in surface code quantum computing.

Findings

Achieves 1.0% accuracy threshold in simulations

Power consumption of 2.78 μW at 2 GHz operation

Decodes surface codes with distances 5 to 13 effectively

Abstract

Due to the low error tolerance of a qubit, detecting and correcting errors on it is essential for fault-tolerant quantum computing. Surface code (SC) associated with its decoding algorithm is one of the most promising quantum error correction (QEC) methods. % One of the challenges of QEC is its high complexity and computational demand. QEC needs to be very power-efficient since the power budget is limited inside of a dilution refrigerator for superconducting qubits by which one of the most successful quantum computers (QCs) is built. In this paper, we propose an online-QEC algorithm and its hardware implementation with SFQ-based superconducting digital circuits. We design a key building block of the proposed hardware with an SFQ cell library and evaluate it by the SPICE-level simulation. Each logic element is composed of about 3000 Josephson junctions and power consumption is about 2.78 uW when operating with 2 GHz clock frequency which meets the required decoding speed. Our decoder is simulated on a quantum error simulator for code distances 5 to 13 and achieves a 1.0% accuracy threshold.