Cold-Atom Buoy: A Differential Magnetic Sensing Technique in Cold Quadrupole Trapshttps://hdl.handle.net/21.15109/ARP/HQN8RTKurkó, ÁrpádNagy, DávidSimon, AlexandraClark, Thomas W.Dombi, AndrásVarga, DánielWilliams, Francis B.Fortágh, JózsefDomokos, PeterVukics, AndrásARP2026-04-132026-04-13T12:31:31ZWe present a differential technique for vector magnetic sensing based on a cold- atom cloud in a magnetic quadrupole trap. An external homogeneous magnetic field displaces the trap center in a direction and magnitude proportional to the field. By reversing the quadrupole polarity between experimental shots and comparing the resulting cloud positions, we extract a differential displacement signal that is free from common-mode effects such as gravity and weak magnetic- field inhomogeneities. The signal is directionally proportional to the external field and requires only absorption imaging, without spectroscopic interrogation. Assuming micron-scale position resolution, the technique enables field resolution at the milli-Gauss level. It offers a practical tool for field compensation in magnetically sensitive experimental stages, bridging operational regimes from Earth-level fields to atomic magnetometry. A straightforward extension to full three-dimensional sensing is possible with only a minimal addition to standard cold-atom infrastructure.Physicscold atomsquantum sensingmagnetic sensingdifferential metrologyÁ. Kurkó et al. : “Cold-Atom Buoy: A Differential Magnetic Sensing Technique in Cold Quadrupole Traps”2026-04-13Curko, Árpád2026-04-072025-09-112025-11-10Experimental data (image data)CC BY-NC 4.0