Hyperpolarized Molecular Nuclear Spins Achieve Magnetic Amplification

TL;DR

This paper demonstrates a novel method using hyperpolarized molecular nuclear spins to achieve significantly enhanced magnetic sensitivity, surpassing current magnetometers, with potential applications in quantum sensing and fundamental physics.

Contribution

The authors introduce a new approach to magnetic amplification using hyperpolarized molecular nuclear spins, achieving over 10% amplification and revealing dispersive effects, advancing quantum sensor technology.

Findings

Orders-of-magnitude enhanced magnetic responsivity.

Magnetic amplification exceeding 10%.

Dispersive frequency-dependent amplification observed.

Abstract

The use of nuclear spins as physical sensing systems is disadvantaged by their low signal responsivity, particularly when compared to sensing techniques based on electron spins. This primarily results from the small nuclear gyromagnetic ratio and the difficulties in achieving high spin polarization. Here we develop a new approach to investigating the response of hyperpolarized molecular nuclear spins to magnetic fields and demonstrate orders-of-magnitude enhanced magnetic responsivity over state-of-the-art proton and Overhauser magnetometers. Using hyperpolarized molecules with proton spins, we report the realization of magnetic amplification in linear and nonlinear types. We further extend this amplification to hyperpolarized scalar-coupled multi-spin molecules and observe substantial magnetic amplification exceeding 10%. Moreover, we observe an anomalous amplification with dispersive frequency dependence that originates from magnetic interference effects. Our work highlights the potential of hyperpolarized molecular nuclear spins for use in a new class of quantum sensors, with promising applications in both applied and fundamental physics, including highly accurate absolute magnetometry and the exploration of axion-nucleon exotic interactions.