A simple magnetic field stabilization technique for atomic Bose-Einstein condensate experiments

TL;DR

This paper presents a straightforward magnetic field stabilization method for Bose-Einstein condensate experiments, achieving microgauss-level stability by compensating current fluctuations with an auxiliary coil, enhancing the precision of atomic interaction studies.

Contribution

A simple, effective magnetic field stabilization technique using auxiliary coils and precise current fluctuation compensation for BEC experiments.

Findings

Achieved magnetic field stability of 64 μG rms at 57 G.

Demonstrated the method's effectiveness in reducing shot-to-shot fluctuations.

Enabled improved conditions for studying three-body interactions in potassium BECs.

Abstract

We demonstrate a simple magnetic field stabilization technique in a Bose-Einstein condensate experiment. Our technique is based on the precise measurement of the current fluctuations in the main magnetic field coils and amounts to their compensation using an auxiliary coil. It has the advantage of simplicity as compensation is done using a low inductance coil that can be straightforwardly driven at the relevant frequencies (1 kHz). The performances of the different components (power supply, current transducer, electronics...) are precisely characterized. In addition, for optimal stability the ambient magnetic field is also measured and compensated. The magnetic field stability around 57 G is measured by Ramsey spectroscopy of magnetic field sensitive radiofrequency transition between two spin states of potassium 39 and the shot-to-shot fluctuations are reduced to 64(7) $\mu$G rms, i.e. at the 1 x 10 -6 level. In the context of our experiment, this result opens interesting prospects for the study of three-body interactions in Bose-Einstein condensate potassium spin mixtures.