Linear optical quantum computing with a hybrid squeezed-cat code

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.