Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Log inSign up
Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Blog
Job Board
Q3AS

© 2026 Aqora Quantum S.A.S.

TermsPrivacyLegal Notice

arXiv:1909.11257 · Review of Scientific Instruments

A digital feedback controller for stabilizing large electric currents to the ppm level for Feshbach resonance studies

Ryan Thomas, Niels Kjærgaard

Published Mar 1, 2020• 16 citations
arXivHTMLPDF

Abstract

Magnetic Feshbach resonances are a key tool in the field of ultracold quantum gases, but their full exploitation requires the generation of large, stable magnetic fields up to 1000 G with fractional stabilities of better than 10−4. Design considerations for electromagnets producing these fields, such as optical access and fast dynamical response, mean that electric currents in excess of 100 A are often needed to obtain the requisite field strengths. We describe a simple digital proportional-integral-derivative current controller constructed using a field-programmable gate array and off-the-shelf evaluation boards that allows for gain scheduling, enabling optimal control of current sources with non-linear actuators. Our controller can stabilize an electric current of 337.5 A to the level of 7.5 × 10−7 in an averaging time of 10 min and with a control bandwidth of 2 kHz.

DOI
10.1063/1.5128935

Related papers

Magnetic field stabilization system designed for the cold-atom coherent population-trapping clock

Zhan Chang, Zhu Ma, Jiatao Wu +4 more

Accurate control of magnetic fields is crucial for cold-atom experiments, often necessitating custom-designed control systems due to limitations in commercially available power supplies.Here, we demonstrate precise and flexible control of a static magnetic field by employing a field-programmable gate array and a feedback loop.This setup enables us to maintain exceptionally stable current with a fractional stability of 1 ppm within 30 s.The error signal of the feedback loop exhibited a noise level of 10 -5 A•Hz -1/2 for control bandwidths below 10 kHz.Utilizing this precise magnetic field control system, we investigate the second-order Zeeman shift in the context of cold-atom coherent population-trapping (CPT) clocks.Our analysis reveals the second-order Zeeman coefficient to be 574.21Hz/G 2 , with an uncertainty of 1.36 Hz/G 2 .Consequently, the magnetic field stabilization system we developed allows us to achieve a second-order Zeeman shift below 10 -14 , surpassing the long-term stability of current cold-atom CPT clocks.

Chinese Optics Letters•Jan 1, 2024•5 citations

A battery-powered floating current source of 100 A for precise and fast control of magnetic field

Yu-Meng Yang, Bo Xiao, Wen-Chao Ji +5 more

In various leading-edge ultracold atom experiments in fields such as quantum simulation, quantum computing, and quantum precision measurement, precise and fast control of the magnetic field is important and a current source with a low noise level and high control bandwidth is required. Conventional commercial current sources, even the expensive ones, may not meet the requirements. Here, we present a battery-powered current source (BPCS) solution that has a maximum output of 100 A with a root-mean-square noise of about only 0.35 mA (integrated from 1 Hz to 3 MHz) and a control bandwidth of about 10 kHz. The large output current is sourced from a lead-acid battery, a fluxgate current sensor is used to detect the output current, and fast feedback regulation is done by using an insulated-gate bipolar transistor under the control of an analog proportional-integral controller. The battery power method eliminates the switching noise. A prepulse method is applied to shorten the settling time when the current steps down from a high level to a low level that is close to zero. These features make the BPCS a suitable analog-controlled floating current source for cold-atom experiments such as the preparation of a single 2D quantum gas and optical lattice atomic clocks.

AIP Advances•Dec 1, 2020•3 citations

Active stabilization of kilogauss magnetic fields to the ppm level for magnetoassociation on ultranarrow Feshbach resonances

Mateusz Borkowski, Lukas Reichsöllner, Premjith Thekkeppatt +4 more

Feshbach association of ultracold molecules using narrow resonances requires exquisite control of the applied magnetic field. Here, we present a magnetic field control system to deliver magnetic fields of over 1000 G with ppm-level precision integrated into an ultracold-atom experimental setup. We combine a battery-powered, current-stabilized power supply with active feedback stabilization of the magnetic field using fluxgate magnetic field sensors. As a real-world test, we perform microwave spectroscopy of ultracold Rb atoms and demonstrate an upper limit on our magnetic field stability of 2.4(3) mG at 1050 G [2.3(3) ppm relative] as determined from the spectral feature.

arXiv:2303.13682•Review of Scientific Instruments•Jul 1, 2023•19 citations

Direct control of high magnetic fields for cold atom experiments based on NV centers

Alexander Hesse, Kerim Köster, Jakob M. Steiner +5 more

Abstract In ultracold quantum gases, the interactions between the individual atoms can be controlled by applying magnetic bias fields. As magnetic field fluctuations limit the precision here, typically a feedback loop needs to be employed to regulate the current through a pair of Helmholtz coils. No commercially available magnetic field sensor allows to measure large fields directly with high enough precision, leading to many unsatisfactory solutions being used in experiments. Here, we demonstrate a direct magnetic field stabilization in a regime previously not accessible, using NV centers as the magnetic field sensor. This allows us to measure and stabilize fields of 4.66 mT down to 12 nT RMS noise over the course of 24 h, measured on a 1 Hz bandwidth. We achieve a control of better than 1 ppm after 20 min of integration time, ensuring high long-term stability for experiments. This approach extends direct magnetic field control to strong magnetic fields, which could enable new precise quantum simulations in this regime.

arXiv:2003.08101•New Journal of Physics•Feb 1, 2021•8 citations

Design of compact coils and a big stable current driver for Feshbach resonance researches

Shuai Chen

Atomic Feshbach resonance is one of the important tools in quantum gases experiments.The position of a resonance,B0,typically occurs at a few hundred gauss for alkali atoms.The width of a resonance Δ can be relatively smaller,thus requires a stable magnetic field.A set of compact Helmholtz coils were designed,which are capable of carrying a high current for the strong magnetic field while maintaining the required stability.The negative integral feedback loop was used to regulate a current stability up to 10-5.

•Jan 1, 2012•0 citations

Magnetic Field Manipulation Applied to Feshbach Resonances in Ultracold Quantum Gases

Tianwei Zhou, Tian Luan, Chen Li +2 more

With a feedforward feedback compound control current servo loop, we present Bitter-type electromagnets featuring high magnetic field and fine electronic properties applied to Feshbach Resonances in Ultracold Quantum Gases.

Journal of Physics Conference Series•Sep 7, 2015•0 citations
Magnetic Feshbach resonances are a key tool in the field of ultracold quantum gases, but their full exploitation requires the generation of large, stable magnetic fields up to 1000 G with fractional stabilities of better than 10−4. Design considerations for electromagnets producing these fields, such as optical access and fast dynamical response, mean that electric currents in excess of 100 A are often needed to obtain the requisite field strengths. We describe a simple digital proportional-integral-derivative current controller constructed using a field-programmable gate array and off-the-shelf evaluation boards that allows for gain scheduling, enabling optimal control of current sources with non-linear actuators. Our controller can stabilize an electric current of 337.5 A to the level of 7.5 × 10−7 in an averaging time of 10 min and with a control bandwidth of 2 kHz.
Accurate control of magnetic fields is crucial for cold-atom experiments, often necessitating custom-designed control systems due to limitations in commercially available power supplies.Here, we demonstrate precise and flexible control of a static magnetic field by employing a field-programmable gate array and a feedback loop.This setup enables us to maintain exceptionally stable current with a fractional stability of 1 ppm within 30 s.The error signal of the feedback loop exhibited a noise level of 10 -5 A•Hz -1/2 for control bandwidths below 10 kHz.Utilizing this precise magnetic field control system, we investigate the second-order Zeeman shift in the context of cold-atom coherent population-trapping (CPT) clocks.Our analysis reveals the second-order Zeeman coefficient to be 574.21Hz/G 2 , with an uncertainty of 1.36 Hz/G 2 .Consequently, the magnetic field stabilization system we developed allows us to achieve a second-order Zeeman shift below 10 -14 , surpassing the long-term stability of current cold-atom CPT clocks.
In various leading-edge ultracold atom experiments in fields such as quantum simulation, quantum computing, and quantum precision measurement, precise and fast control of the magnetic field is important and a current source with a low noise level and high control bandwidth is required. Conventional commercial current sources, even the expensive ones, may not meet the requirements. Here, we present a battery-powered current source (BPCS) solution that has a maximum output of 100 A with a root-mean-square noise of about only 0.35 mA (integrated from 1 Hz to 3 MHz) and a control bandwidth of about 10 kHz. The large output current is sourced from a lead-acid battery, a fluxgate current sensor is used to detect the output current, and fast feedback regulation is done by using an insulated-gate bipolar transistor under the control of an analog proportional-integral controller. The battery power method eliminates the switching noise. A prepulse method is applied to shorten the settling time when the current steps down from a high level to a low level that is close to zero. These features make the BPCS a suitable analog-controlled floating current source for cold-atom experiments such as the preparation of a single 2D quantum gas and optical lattice atomic clocks.
Feshbach association of ultracold molecules using narrow resonances requires exquisite control of the applied magnetic field. Here, we present a magnetic field control system to deliver magnetic fields of over 1000 G with ppm-level precision integrated into an ultracold-atom experimental setup. We combine a battery-powered, current-stabilized power supply with active feedback stabilization of the magnetic field using fluxgate magnetic field sensors. As a real-world test, we perform microwave spectroscopy of ultracold Rb atoms and demonstrate an upper limit on our magnetic field stability of 2.4(3) mG at 1050 G [2.3(3) ppm relative] as determined from the spectral feature.
Abstract In ultracold quantum gases, the interactions between the individual atoms can be controlled by applying magnetic bias fields. As magnetic field fluctuations limit the precision here, typically a feedback loop needs to be employed to regulate the current through a pair of Helmholtz coils. No commercially available magnetic field sensor allows to measure large fields directly with high enough precision, leading to many unsatisfactory solutions being used in experiments. Here, we demonstrate a direct magnetic field stabilization in a regime previously not accessible, using NV centers as the magnetic field sensor. This allows us to measure and stabilize fields of 4.66 mT down to 12 nT RMS noise over the course of 24 h, measured on a 1 Hz bandwidth. We achieve a control of better than 1 ppm after 20 min of integration time, ensuring high long-term stability for experiments. This approach extends direct magnetic field control to strong magnetic fields, which could enable new precise quantum simulations in this regime.
Atomic Feshbach resonance is one of the important tools in quantum gases experiments.The position of a resonance,B0,typically occurs at a few hundred gauss for alkali atoms.The width of a resonance Δ can be relatively smaller,thus requires a stable magnetic field.A set of compact Helmholtz coils were designed,which are capable of carrying a high current for the strong magnetic field while maintaining the required stability.The negative integral feedback loop was used to regulate a current stability up to 10-5.