Dual-rail Fluxonium Erasure Qubit

Implementing quantum error correction with erasure qubits and erasure error detection is understood to have advantages in both error threshold and code distance. To further improve the performance of the logical qubit and reduce the number of necessary physical qubits, we aim to design erasure qubits that have both low erasure error rate (<1%) and low logical error rate (<0.1%). We propose to achieve this goal by building a dual-rail erasure qubit in the form of two capacitively coupled fluxonium qubits. In this presentation, we show the basic system performance and benchmarks. We analyze the coherence properties of the fluxonium qubits in this system. We implement the erasure checks on the dual-rail qubit and evaluate their backactions.