Cost-reduced all-Gaussian universality with the Gottesman-Kitaev-Preskill code: Resource-theoretic approach to cost analysis

The authors present a new mechanism to prepare magic states of the Gottesman-Kitaev-Preskill (GKP) continuous-variable quantum error-correcting code from two perspectives. The paper proposes two methods: a cost-reduced scheme of universal quantum computation by experimentally tractable Gaussian operations using the GKP magic states as a single resource, and the formulation of a resource-theoretical method for quantitatively analyzing the usefulness of magic states of the GKP code.