Abstract
Bosonic quantum error correction (QEC) protocols encode and protect quantum information in the phase space of a quantum harmonic oscillator, offering a hardware-efficient path towards fault-tolerant quantum computing. To control the encoded information, a nonlinear element, such as a qubit, is coupled to the harmonic oscillator. With superconducting circuits, bosonic QEC has been achieved within the high-Q harmonic mode of a 3D microwave cavity dispersively coupled to a fixed-frequency transmon qubit. However, all previous demonstrations have been limited by bit-flips in the transmon control qubit and have been performed in 3D cavity architectures. We instead use a heavy fluxonium as a control qubit which can offer improved bit-flip lifetimes, coupled to a thousand-times smaller coplanar waveguide resonator in an extensible 2D architecture. Moreover, by tuning an external flux bias, we can decouple the fluxonium and harmonic oscillator in-situ to prevent backaction on the encoded information during parts of the error correction protocol. In this second part of a two-part talk, we will share results on the creation, stabilization, and manipulation of a Gottesman-Kitaev-Preskill qubit in our planar architecture.
*This research was funded in part by the Army Research Office under Award Number W911NF-23-1-0045; in part by the U.S. Department of Energy, Office of Science, National Quantum Information Science Research Centers, Co-design Center for Quantum Advantage (C2QA) under contract number DE-SC0012704; in part by the AWS Center for Quantum Computing; and in part under Air Force Contract No. FA8702-15-D-0001. M. H. acknowledges funding from the IC Postdoctoral Fellowship. S. R. J. and S. C. acknowledge support from the NSF Graduate Research Fellowship. The views and conclusions contained herein are those of the authors and should not be interpreted as necessarily representing the official policies or endorsements, either expressed or implied, of the U.S. Government.
