In situ magnetic-field stabilization for quantum-gas experiments
Phys. Rev. Applied 26, 014104 – Published 31 July, 2026
DOI: https://doi.org/10.1103/vpnl-xpj7
Abstract
We demonstrate a minimally destructive in situ technique for measuring and stabilizing slowly drifting magnetic fields in ultracold-atom experiments. While conventional magnetic-field sensors such as Hall, giant magnetoresistive, or fluxgate-based devices are broadly used, their accuracy, precision, and dynamic range can be limited. In addition, these sensors are typically positioned at least several centimeters away from the in-vacuum atomic system, as their operation creates perturbing magnetic fields, and their placement is limited by geometric constraints imposed by the vacuum system. We overcome these issues by using the atomic system itself as a built-in magnetometer. To that end, we employ a pair of weak measurements to determine the Zeeman splitting—and thereby the magnetic field—of a magnetically sensitive atomic transition. We provide closed-form expressions quantifying the trade-offs among measurement noise, dynamic range, and atom loss. This procedure is demonstrated with ultracold , weakly measured using partial-transfer absorption imaging. We then incorporate a Kalman filter to stabilize the magnetic field; this eliminated long-term drift in the ambient field (as high as approximately 70 nT/hr) in exchange for a modest increase in shot-to-shot variability from 1.8(2) to 2.0(2) nT.
