Magnetic resonance with squeezed microwaves

TL;DR

This paper demonstrates that using squeezed microwave fields can reduce noise and improve the sensitivity of magnetic resonance spectroscopy at millikelvin temperatures, showcasing quantum metrology's potential in this field.

Contribution

It introduces the application of squeezed microwave states to enhance magnetic resonance detection sensitivity, a novel approach in quantum sensing.

Findings

Achieved 1.2 dB noise reduction with squeezed microwaves

Proof of principle for quantum-enhanced magnetic resonance spectroscopy

Potential for improved measurement sensitivity in quantum sensing

Abstract

Vacuum fluctuations of the electromagnetic field set a fundamental limit to the sensitivity of a variety of measurements, including magnetic resonance spectroscopy. We report the use of squeezed microwave fields, which are engineered quantum states of light for which fluctuations in one field quadrature are reduced below the vacuum level, to enhance the detection sensitivity of an ensemble of electronic spins at millikelvin temperatures.} By shining a squeezed vacuum state on the input port of a microwave resonator containing the spins, we obtain a $1.2$\,dB noise reduction at the spectrometer output compared to the case of a vacuum input. This result constitutes a proof of principle of the application of quantum metrology to magnetic resonance spectroscopy.