Logical Gates on Grid Codes with Gaussian Operations, Part 3: Experiments

Qubits encoded in the large Hilbert spaces of harmonic oscillators with bosonic codes constitute a hardware-efficient approach to quantum computing. In recent years, the Gottesman-Kitaev-Preskill (GKP) code [1] has been used to demonstrate quantum error correction (QEC) beyond break-even [2] and to perform autonomous QEC [3]. For computation, a complete single- and two-qubit gate set that is compatible with GKP QEC is required. Implementing gates with coupler-mediated Gaussian interactions leads to a form of fault-tolerance in that any gate-induced errors are correctable by QEC. In this talk, we present experimental results on two such Gaussian interactions, single-mode squeezing and beamsplitter operations, which form the underlying primitives for a single-qubit phase gate and two-qubit CNOT/CZ gates respectively.

[1] D. Gottesman, A. Kitaev, and J. Preskill, Phys. Rev. A 64, 012310 (2001)

[2] V. V. Sivak et al., Nature 616, 55 (2023)

[3] D. Lachance-Quirion et al., Phys. Rev. Lett. 132, 150607 (2024)