Quantum-Ready Microwave Detection with Scalable Graphene Bolometers in the Strong Localization Regime

TL;DR

This paper introduces scalable epitaxial graphene bolometers capable of detecting GHz photons with ultra-low noise, leveraging quantum interference and charge localization to significantly improve thermal sensitivity at millikelvin temperatures.

Contribution

The work demonstrates a novel graphene-based bolometer design with enhanced thermal conductance control, achieving record low noise levels for quantum detection applications.

Findings

Achieved a noise equivalent power of 40 zW/√Hz at 40 mK.

Utilized strong charge localization to reduce thermal conductance.

Enabled GHz photon detection relevant for quantum processors.

Abstract

Exploiting quantum interference of charge carriers, epitaxial graphene grown on silicon carbide emerges as a game-changing platform for ultra-sensitive bolometric sensing, featuring an intrinsic resistive thermometer response unmatched by any other graphene variant. By achieving low and uniform carrier densities, we have accessed a new regime of strong charge localization that dramatically reduces thermal conductance, significantly enhancing bolometer performance. Here we present scalable graphene-based bolometers engineered for detecting GHz-range photons, a frequency domain essential for superconducting quantum processors. Our devices deliver a state-of-the-art noise equivalent power of 40 zW$/\sqrt{\rm Hz}$ at $T=40~$mK, enabled by the steep temperature dependence of thermal conductance, $G_{\rm th}\sim T^4$ for $T<100~$mK. These results establish epitaxial graphene bolometers as versatile and low-back-action detectors, unlocking new possibilities for next-generation quantum processors and pioneering investigations into the thermodynamics and thermalization pathways of strongly entangled quantum systems.