Magnetic field-resilient quantum-limited parametric amplifier

TL;DR

This paper introduces a magnetic field-resilient, quantum-limited parametric amplifier based on NbN nanobridge kinetic inductance, enabling high gain and low noise performance in magnetic environments, suitable for advanced quantum applications.

Contribution

We developed a NbN nanobridge kinetic inductance parametric amplifier that maintains quantum-limited noise performance under strong magnetic fields, unlike traditional Josephson junction-based amplifiers.

Findings

Achieved up to 42 dB gain with low added noise (~0.59 quanta)

Maintained amplifier performance in magnetic fields up to 427 mT

Demonstrated potential for quantum sensing and particle searches

Abstract

Superconducting parametric amplifiers are crucial components in microwave quantum circuits for enabling quantum-limited signal readout. The best-performing such amplifiers are often based on Josephson junctions, which however are sensitive to magnetic fields. Therefore, they require magnetic shields and are not easily integratable with other quantum systems that operates within magnetic fields, such as spin ensemble quantum memories. To tackle this challenge, we have developed a kinetic inductance-based parametric amplifier featuring a NbN nanobridge instead of Josephson Junctions, which provides the desired nonlinearity for a strong parametric gain up to 42 dB. The added noise of this nanobridge kinetic-inductance parametric amplifier (hereby referred as NKPA) is calibrated and found to be $0.59\pm 0.03$ quanta for phase-preserving amplification, approaching the quantum limit of 0.5 quanta. Most importantly, we show that such excellent noise performance is preserved in an in-plane magnetic field up to 427 mT, the maximum field available in our experiment. This magnetic field-resilient parametric amplifier presents an opportunity towards addressing single electron-spin resonance and more efficient search for Axions as well as Majorana Fermions.