Fluxonium as Ancillary Qubit for Modular Quantum Computing
Abstract: Modular network is a promising architecture for entangling multiple qubits. Each module should consist of a qubit or cavity for storing quantum information, and an ancillary resonator or qubit for manipulating stored states. A common choice for an ancillary qubit is the transmon. However, the fidelity of entanglement is often corrupted by the coherence time, or the weakly anharmonic nature of transmon that limits the speed of the parametric interaction. Here, we explore the idea of replacing the transmon with a high-coherence fluxonium qubit as an ancillary qubit. We also use a SNAIL as a three wave mixing element to mediate the otherwise forbidden transition between fluxonium excitation and photons. This talk will focus on the design of SNAIL-fluxonium, and driving forbidden transitions with it. This will be useful in the cooling of the fluxonium qubit, as well as swapping excitations between qubits and photonic links. With carefully designed qubit parameters, it is possible to have a high-coherence ancillary qubit, and therefore achieve high fidelity inter-chip entanglement between superconducting modules.
Student Information: Ke Nie is a 2nd year physics graduate student working for Angela Kou researching remote entanglement between fluxonium qubits.
