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

Abstract

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.

Observation of Massless and Massive Collective Excitations with Faraday Patterns in a Two-Component Superfluid

“…4(b). Small deviations are due to shotto-shot noise in the bias field, that remains below 10 Hz thanks to the magnetic shield in our apparatus [25]. The coherence of the oscillation has a 1/e lifetime of about 150 ms, compatible with the expected coherence lifetime due to atom losses, mainly induced by the coupling through the lossy state |2, 0 .…”

“…In order to observe collective behaviors in the spin channel, we need to have Ω R < 2µ s , a condition which ensures also that the adiabaticity condition is fulfilled, having ω p ω ⊥ . Operating in this regime is experimentally possible thanks to the µG-level stability in the magnetic field that is provided by the magnetic shielding surrounding our setup [19,25]. This magnetic field stability corresponds to a frequency stability of the atomic resonance at the level of a few Hz.…”

Experimentally Realizing Efficient Quantum Control with Reinforcement Learning

“…After a high pass filter (HPF), this signal will be amplified to about 10 W and then transmitted to the ion with a microwave horn [51]. Our trap device is shielded with a 1.5 mm thick single layer Mu-metal [52], making the final coherence time about 200 ms for |0 ↔ |1 transition, which is characterized by Ramsey experiments.…”

Manipulation of an elongated internal Josephson junction of bosonic atoms

“…Atoms are initially prepared in the |F, m F = |1, −1 state (later referred as |↓ ), where F is the total atomic angular momentum and m F its projection on the quantization axis set by a uniform and highly stable magnetic field of 1.3 G. The shot-to-shot stability [22] of the magnetic field is at the level of a few µG over tens of minutes of continuous experimental cycling.…”