Publications using HERD

Experiments on superconducting qubits, including work on quasiparticle tunneling, coherence, and high-fidelity readout.

14 publications shown
Figure from Recovery dynamics of a gap-engineered transmon after a quasiparticle burst
2025·Yale University·Quasiparticle bursts

Recovery dynamics of a gap-engineered transmon after a quasiparticle burst

Gap-engineered transmons show reduced sensitivity to quasiparticle bursts, but substrate heating during an impact lets quasiparticles overcome the engineered gap. Relaxation recovers in ~0.7 ms, while chip heating persists for several milliseconds.

doi.org/10.48550/arXiv.2505.08104
Figure from 2D transmons with lifetimes and coherence times exceeding 1 millisecond
2025·Princeton University·Coherence times

2D transmons with lifetimes and coherence times exceeding 1 millisecond

Tantalum transmons on high-resistivity silicon achieve 2D qubit lifetimes up to ~1.7 ms and echo coherence exceeding T₁, while supporting 99.994% single-qubit gate fidelity on a wafer-scalable platform.

doi.org/10.48550/arXiv.2503.14798
Figure from A transmon qubit realized by exploiting the superconductor-insulator transition
2025·Yale University·NbN junctions

A transmon qubit realized by exploiting the superconductor-insulator transition

Demonstrates a transmon-type qubit made from an NbN thin film weak link created by tuning near the superconductor–insulator transition. The junction-less design avoids oxide barriers and parasitic capacitance, showing feasibility of planar, high-gap superconducting qubits.

doi.org/10.48550/arXiv.2510.19983
Figure from Direct detection of quasiparticle tunneling with a charge-sensitive superconducting sensor coupled to a waveguide
2024·Chalmers University of Technology·Quasiparticle detection

Direct detection of quasiparticle tunneling with a charge-sensitive superconducting sensor coupled to a waveguide

Demonstrates real-time detection of quasiparticle tunneling events using a transmon directly coupled to a waveguide. Achieves tunneling rates between 0.8 and 7 s⁻¹ with temporal resolution below 10 μs without quantum-limited amplification.

doi.org/10.48550/arXiv.2404.01277
Figure from rf-SQUID-based traveling-wave parametric amplifier with input saturation power of −84 dBm across more than one octave in bandwidth
2025·PTB·Parametric amplifiers

rf-SQUID-based traveling-wave parametric amplifier with input saturation power of −84 dBm across more than one octave in bandwidth

Demonstrates an rf-SQUID-based Josephson TWPA with -84 dBm average saturation power and ~20 dB gain over 3.5-8.5 GHz, achieving near-quantum-limited noise with 0.8-1.5 photons excess noise.

doi.org/10.1103/1qk4-fzkq
Figure from Lumped-element broadband SNAIL parametric amplifier with on-chip pump filter for multiplexed readout
2025·Yale University·Parametric amplifiers

Lumped-element broadband SNAIL parametric amplifier with on-chip pump filter for multiplexed readout

Describes a broadband SNAIL amplifier with integrated matching network and on-chip pump filtering, enabling wideband multiplexed qubit readout with improved isolation.

doi.org/10.1103/5l86-pw21