Linear optical quantum computing with a hybrid squeezed cat code

TL;DR

This paper introduces a hybrid squeezed cat code for optical quantum computing, combining squeezed cat and polarization qubits, which can be implemented with linear optics and shows improved performance over existing codes.

Contribution

It proposes a new hybrid code that integrates squeezed cat and polarization qubits, along with a generation method and universal gates using linear optics.

Findings

Hybrid squeezed cat code outperforms hybrid cat and squeezed cat codes in simulations.

The proposed method enables fault-tolerant optical quantum computing with current technology.

Linear optical implementation of the code is feasible and efficient.

Abstract

In recent years, squeezed cat codes with resilience to specific types of loss have been proposed as a step toward realizing fault-tolerant optical quantum computers. However, error correction for squeezed cat codes requires a strong nonlinearity, which makes its implementation challenging with current technology. We propose a novel hybrid code that combines the squeezed cat code and the polarization qubit. First, we propose a generation method and a universal gate set that can be implemented with a linear optical system. Then, we show the superiority of the hybrid squeezed cat code over the hybrid cat code and the squeezed cat code through numerical simulations. These results demonstrate that the hybrid squeezed cat code is a promising candidate as a new resource for optical quantum information processing.