Magnetic field stabilization system for atomic physics experiments

Merkel, Benjamin; Thirumalai, K.; Tarlton, James E.; Schäfer, Vera M.; Ballance, C. J.; Harty, T. P.; Lucas, David M.

doi:10.1063/1.5080093

Cited by 59 publications

(35 citation statements)

References 25 publications

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“…Passive magnetic shielding is well-suited for isolating an experiment by excluding magnetic fields from a contained volume. As opposed to active stabilisation 10,16 or dynamical decoupling 17,18 , it uses materials that have high magnetic permeability µ r and so redirect the magnetic flux lines around the enclosed volume. Different materials have different properties and utilise different shielding mechanisms: high-µ r materials screen quasi-dc fields up to a few 100 Hz by flux-shunting, while highly conductive materials cancel magnetic fields induced by eddy currents oscillating at a few kHz 19,20 .…”

Section: Introductionmentioning

confidence: 99%

Design and characterization of a compact magnetic shield for ultracold atomic gas experiments

Farolfi

Trypogeorgos

Colzi

et al. 2019

Review of Scientific Instruments

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We report on the design, construction, and performance of a compact magnetic shield that facilitates a controlled, low-noise environment for experiments with ultracold atomic gases. The shield was designed to passively attenuate external slowly-varying magnetic fields while allowing for ample optical access. The geometry, number of layers and choice of materials were optimised using extensive finite-element numerical simulations. The measured performance of the shield is in good agreement with the simulations. From measurements of the spin coherence of an ultracold atomic ensemble we demonstrate a remnant field noise of 2.6 µG and a suppression of external dc magnetic fields by more than five orders of magnitude.

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Section: Introductionmentioning

confidence: 99%

Design and characterization of a compact magnetic shield for ultracold atomic gas experiments

Farolfi

Trypogeorgos

Colzi

et al. 2019

Review of Scientific Instruments

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“…More recently, it was reported that a very low noise magnetic field was generated for an experiment on trapped ion system. By combining feed-forward and dynamic feedback techniques, a reduced environmental noise of 43µG, with the bias magnetic field of 146G, has also been achieved 31 .…”

Section: Introductionmentioning

confidence: 99%

Ultra-low noise magnetic field for quantum gases

Wang

Jiao

et al. 2019

Review of Scientific Instruments

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Ultra-low noise magnetic field is essential for many branches of scientific research. Examples include experiments conducted on ultra-cold atoms, quantum simulations, as well as precision measurements. In ultra-cold atom experiments specifically, a bias magnetic field will be often served as a quantization axis and be applied for Zeeman splitting. As atomic states are usually sensitive to magnetic fields, a magnetic field characterized by ultra-low noise as well as high stability is typically required for experimentation. For this study, a bias magnetic field is successfully stabilized at 14.5G, with the root mean square (RMS) value of the noise reduced to 18.5µG (1.28ppm) by placing µ-metal magnetic shields together with a dynamical feedback circuit. Long-time instability is also regulated consistently below 7µG. The level of noise exhibited in the bias magnetic field is further confirmed by evaluating the coherence time of a Bose-Einstein condensate characterized by Rabi oscillation. It is concluded that this approach can be applied to other physical systems as well.

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“…In ErYb K μ (B res ) are largest for small fields, where for B<100 G we can expect many resonances with K μ (B res ) of a few hundred. Given that magnetic fields can be controlled experimentally up to about 10 −6 (active magnetic field stabilization to 0.29 ppm was recently demonstrated [82]), the positions of Feshbach resonances could constrain the variations of proton-to-electron mass ratio up to about 10 −8 -10 −9 at best. Much more useful constraints could potentially be achieved by monitoring the scattering length near a Feshbach resonance [79].…”

Section: Sensitivity Of Feshbach Spectra To Variations Of Reduced Massmentioning

confidence: 99%

Quantum chaos in Feshbach resonances of the ErYb system

2020

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We investigate ultracold magnetic-field-assisted collisions in the so far unexplored ErYb system. The nonsphericity of the Er atom leads to weakly anisotropic interactions that provide the mechanism for Feshbach resonances to emerge. The resonances are moderately sparsely distributed with a density of 0.1-0.3 G −1 and exhibit chaotic statistics characterized by a Brody parameter η≈0.5-0.7. The chaotic behaviour of Feshbach resonances is accompanied by strong mixing of magnetic and rotational quantum numbers in near-threshold bound states. We predict the existence of broad resonances at fields < 300 G that may be useful for the precise control of scattering properties and magnetoassociation of ErYb molecules. The high number of bosonic Er-Yb isotopic combinations gives many opportunities for mass scaling of interactions. Uniquely, two isotopic combinations have nearly identical reduced masses (differing by less than 10 −5 relative) that we expect to have strikingly similar Feshbach resonance spectra, which would make it possible to experimentally measure their sensitivity to hypothetical variations of proton-to-electron mass ratio. behaviour can be analyzed instead (see pioneering work of Porter and coworkers e.g. [24,25]) and the tools for such analysis include the Random Matrix Theory developed by Wigner [26] and Dyson [27]. For ultracold gases the first evidence of chaos in a Feshbach resonance spectrum was reported in Er dimer by Frisch et al [19]. Since then, the chaotic character of bound states and Feshbach resonances in ultracold collisions was also found for several other systems, for example, in mixtures of Yb atoms in 1 S 0 and 3 P 2 states at large magnetic fields [28], and molecular collisions of Li atom with CaH and CaF [29]. On the other hand, the resonance spacings in collisions of Er and Li atoms in a magnetic field [30], and of highly magnetic europium ( 7 S) with alkali metal atoms [31] have both been shown to follow the non-chaotic poissonian distribution.Here we investigate the interactions and Feshbach spectra between weakly anisotropic lanthanides and heavy spin-singlet atoms using ErYb as a prime example. Ytterbium, alongside Sr, is the most widely used spin-singlet atom with applications for optical clocks, quantum gases and quantum simulation [32][33][34][35]. ErYb should also be very attractive due to the fantastic mass-scalability of both Yb [36,37] and Er (as shown here). Three of the bosonic Yb isotopes, 168 Yb [38] and 170 Yb [39] and 174 Yb [40] form stable Bose-Einstein condensates, and several Fermi and Bose-Fermi and Bose-Bose gases [41, 42] have also been demonstrated experimentally. Er and Yb atoms could form many isotopic mixtures, including two fermion-fermion mixtures with nearly equal masses and very close polarizabilities (hence, trapping properties). While an Er-Yb quantum degenerate mixture has not been achieved yet, it is clearly within the reach of present state-of-the-art techniques. Our predictions could be tested by forming a dual Mott insulator of Er and Yb atoms...

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Magnetic field stabilization system for atomic physics experiments

Cited by 59 publications

References 25 publications

Design and characterization of a compact magnetic shield for ultracold atomic gas experiments

Design and characterization of a compact magnetic shield for ultracold atomic gas experiments

Ultra-low noise magnetic field for quantum gases

Quantum chaos in Feshbach resonances of the ErYb system

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