Gaussian conversion protocols for cubic phase state generation

TL;DR

This paper introduces two Gaussian conversion protocols that transform experimentally achieved non-Gaussian trisqueezed states into cubic phase states, facilitating universal quantum computation with continuous variables.

Contribution

The paper presents novel deterministic and probabilistic Gaussian protocols for converting trisqueezed states into cubic phase states, advancing experimental methods for non-Gaussian resource generation.

Findings

Deterministic protocol achieves high fidelities saturating Gaussian bounds.

Probabilistic protocol removes in-line squeezing requirements with high success probability.

Protocols demonstrate the potential of trisqueezed states as resources for universal quantum computing.

Abstract

Universal quantum computing with continuous variables requires non-Gaussian resources, in addition to a Gaussian set of operations. A known resource enabling universal quantum computation is the cubic phase state, a non-Gaussian state whose experimental implementation has so far remained elusive. In this paper, we introduce two Gaussian conversion protocols that allow for the conversion of a non-Gaussian state that has been achieved experimentally, namely the trisqueezed state [Sandbo Changet al., Phys. Rev. X10, 011011 (2020)],to a cubic phase state. The first protocol is deterministic and it involves active (in-line) squeezing, achieving large fidelities that saturate the bound for deterministic Gaussian protocols. The second protocol is probabilistic and it involves an auxiliary squeezed state, thus removing the necessity of in-line squeezing but still maintaining significant success probabilities and fidelities even larger than for the deterministic case. The success of these protocols provides strong evidence for using trisqueezed states as resources for universal quantum computation.