Single-domain Bose condensate magnetometer achieves energy resolution per bandwidth below ℏ

Abstract

Significance Energy resolution per bandwidth E R is a cross-technology figure of merit that quantifies the combined spatial, temporal, and field resolution of a magnetic sensor. Today’s best-developed magnetometer technologies, including superconducting quantum interference devices, spin-exchange relaxation-free Rb vapors, and nitrogen-vacancy centers in diamond, are limited by quantum noise to E R ≳ ℏ . Meanwhile, important sensing applications, e.g., noninvasive discrimination of individual brain events, would be enabled by E R < ℏ . This situation has motivated proposals for sensors operating by new physical principles. Our result, E R = 0.075 ( 16 ) ℏ , far beyond the best possible performance of established sensor technologies, confirms the potential of this class of proposed sensors. The result opens horizons for condensed matter, neuroscience, and tests of fundamental physics.