Single-quadrature quantum magnetometry in cavity electromagnonics

TL;DR

This paper proposes a cavity electromagnonics-based magnetometer that surpasses the standard quantum limit, offering high sensitivity at room temperature and signal amplification for magnetic field detection.

Contribution

It introduces a novel scheme for quantum magnetometry using cavity electromagnonics, achieving noise reduction and signal amplification beyond existing methods.

Findings

Achieves magnetic field sensitivity around 10^{-18} T/√Hz.

Reduces measurement noise below the standard quantum limit.

Provides room-temperature operation with wide frequency range up to MHz.

Abstract

A scheme of an ultra-sensitive magnetometer in the cavity quantum electromagnonics where the intracavity microwave mode coupled to a magnonic mode via magnetic dipole interaction is proposed. It is shown that by driving both magnonic and microwave modes with external classical fields and controlling the system parameters, one can reduce the added noise of magnetic field measurement below the standard quantum limit (SQL). Surprisingly, we show that beyond the rotating wave approximation (RWA), not only the added noise can be suppressed, but also the output cavity response to the input signal can be substantially amplified in order to achieve a precise magnetic-field measurement. The estimated theoretical sensitivity of the proposed magnetic amplifier-sensor is approximately in the order of $10^{-18}T/\sqrt{Hz}$ which is competitive compared to the current state-of-the-art magnetometers like superconducting quantum interference devices (SQUIDs) and atomic magnetometers. The advantage of the proposed sensor in comparison with the other magnetometers is its high sensitivity at room temperature and sensing in a wide range of frequency up to MHz as well as its capability to signal-response amplification.