Simultaneous monitoring of fluxonium qubits in a waveguide

Abstract

Most quantum-error correcting codes assume that the decoherence of each physical qubit is independent of the decoherence of any other physical qubit. We can test the validity of this assumption in an experimental setup where a microwave feedline couples to multiple qubits by examining correlations between the qubits. Here, we investigate the correlations between fluxonium qubits located in a single waveguide. Despite being in a wide-bandwidth electromagnetic environment, the qubits have measured relaxation times in excess of 100 us. We use cascaded Josephson parametric amplifiers to measure the quantum jumps of two fluxonium qubits simultaneously. No correlations are observed between the relaxation times of the two fluxonium qubits, which indicates that the sources of relaxation are local to each qubit. Our architecture can easily be scaled to monitor larger numbers of qubits.

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• The superconducting quasicharge qubit
• Two-qubit spectroscopy of spatiotemporally correlated quantum noise in superconducting qubits
• Implementation of a transmon qubit using superconducting granular aluminum
• Josephson Array Mode Parametric Amplifier
• Superconducting granular aluminum resonators resilient to magnetic fields up to 1 Tesla
• Gralmonium: Granular Aluminum Nano-Junction Fluxonium Qubit
• Non-degenerate parametric amplifiers based on dispersion engineered Josephson junction arrays
• Quantum non-demolition dispersive readout of a superconducting artificial atom using large photon numbers
• Heralded generation of maximal entanglement in any dimension via incoherent coupling to thermal baths
• Improving autonomous thermal entanglement generation using a common reservoir
• State preparation of a fluxonium qubit with feedback from a custom FPGA-based platform
• Collective bosonic effects in an array of transmon devices
• Electron shelving of a superconducting artificial atom
• Minimizing the discrimination time for quantum states of an artificial atom
• Non-demolition fluorescence readout and high-fidelity unconditional reset of a fluxonium qubit via dissipation engineering
• Simultaneous sweet-spot locking of gradiometric fluxonium qubits