Engineering Sideband Interactions with the Very Small Logical Qubit (VSLQ) Device Part II

We report our experimental progress towards implementing a VSLQ device for the autonomous quantum error correction. As a first step, we modify the original VSLQ superconducting circuit [1] and propose a new parametric modulation scheme for engineering the VSLQ Hamiltonian. The new scheme requires many fewer RF flux lines, which significantly reduces the device operational complexity and substantially mitigates cross-talks between the multiple flux loops. Next, in our experiment, we calibrate the static circuit parameters under DC flux biasing. We then further explore the dynamic behavior of the circuit under RF flux modulation, and demonstrate how to generate different types of sideband interactions from RF flux modulations with appropriately chosen frequencies and phases. These sideband interactions serve not only as critical components of the VSLQ protocol, but can also be used to realize instantaneous qubit interactions along arbitrary axes.

[1] E. Kapit, Phys. Rev. Lett. 116, 150501 (2016).