Superconducting qubits provide a promising platform for achieving scalable quantum information processing. However reaching fault tolerance requires further improvements in qubit coherence times, crosstalk suppression, and qubit control. In this talk, I will discuss our efforts in addressing these challenges. First, I will show how encoding a qubit in robust logical states with disjoint support can provide simultaneous protection against relaxation and pure dephasing. The measured relaxation (1.6ms) and dephasing times (25us) demonstrate the protection in our implementation of the 0-pi qubit. Next, I will show how Floquet engineering can be used to mitigate dephasing due to 1/f noise. In particular, we obtain a 40-fold improvement in the coherence time of a Fluxonium qubit. Lastly, I will show how quantum interference from the coupler energy levels can be harnessed to suppress multiqubit crosstalk, while simultaneously allowing high fidelity two-qubit gates. Our results pave the way towards a fault-tolerant quantum processor.
Zoom link: https://princeton.zoom.us/j/93888682921