Scanning Quantum Cryogenic Atom Microscope

Abstract

Microscopic imaging of local magnetic fields provides a window into the organizing principles of complex and technologically relevant condensed matter materials. However, a wide variety of intriguing strongly correlated and topologically nontrivial materials exhibit poorly understood phenomena outside the detection capability of state-of-the-art high-sensitivity, high-resolution scanning probe magnetometers. We introduce a quantum-noise-limited scanning probe magnetometer that can operate from room-to-cryogenic temperatures with unprecedented DC-field sensitivity and micronscale resolution. The Scanning Quantum Cryogenic Atom Microscope (SQCRAMscope) employs a magnetically levitated atomic Bose-Einstein condensate (BEC), thereby providing immunity to conductive and blackbody radiative heating. The SQCRAMscope has a field sensitivity of 1.4 nT per resolution-limited point (∼2 µm), or 6 nT/ √ Hz per point at its duty cycle. Compared to pointby-point sensors, the long length of the BEC provides a naturally parallel measurement, allowing one to measure nearly one-hundred points with an effective field sensitivity of 600 pT/ √ Hz for each point during the same time as a point-by-point scanner would measure these points sequentially. Moreover, it has a noise floor of 300 pT and provides nearly two orders of magnitude improvement in magnetic flux sensitivity (down to 10 −6 Φ0/ √ Hz) over previous atomic probe magnetometers capable of scanning near samples. These capabilities are, for the first time, carefully benchmarked by imaging magnetic fields arising from microfabricated wire patterns, in a system where samples may be scanned, cryogenically cooled, and easily exchanged. We anticipate the SQCRAMscope will provide charge transport images at temperatures from room-to-4 K in unconventional superconductors and topologically nontrivial materials.

Entanglement-based 3D magnetic gradiometry with an ultracold atomic scattering halo

“…Among these applications, quantum-assisted magnetometry is an active area for a variety of platforms, including superconducting circuits [12], nuclei in molecules [13], nitrogen-vacancy centres in diamond [14], optomechanical microcavities [15], trapped ions [8], atomic vapours [11], and ultracold atoms [16,17]. Excellent wide-field measurements of magnetic fields have been investigated in nitrogen-vacancy centres in diamond [14] and ultracold atomic systems [18]. These magnetic microscopes show promising applications in medical and material science, where a precise mapping of the magnetic field is desired, requiring the combination of microscopic spatial resolution and high measurement precision [19].…”

“…These magnetic microscopes show promising applications in medical and material science, where a precise mapping of the magnetic field is desired, requiring the combination of microscopic spatial resolution and high measurement precision [19]. Ultracold atom microscopes rely on reconstruction of the magnetic field via imaging density modulations in elongated trapped ensembles [18,20], or in-trap atom interferometry [16], while scanning the trapped cloud over the interrogation area, or equivalently by scanning the source of the magnetic field. So far, demonstrations of such wide field-of-view magnetic imaging has been limited to 2D, and quantum correlations are yet to be exploited in such applications.…”

Nematic transitions in iron pnictide superconductors imaged with a quantum gas

“…Shown is the Fe (brown)-As (pink) plane with the tetragonal (t) and orthorhombic (o) crystal axes labeled. (b) A quasi-1D BEC (red) is magnetically confined two-microns from the surface of the pnictide sample using an atom-chip trap (not shown) [1,5]. The crystal forms domains with anisotropic resistivity upon cooling (blue and green stripes).…”

Quantum sensing using imbalanced counter-rotating Bose–Einstein condensate modes

“…In [25], the possibility of taking profit of Feshbach resonances to use a two-component BEC as a magnetometer was also outlined. Ultracold atomic magnetometers based on detecting density fluctuations in a BEC due to the deformation of the trapping potential have also been demonstrated [26][27][28].…”