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

Physical Review Applied

Atomic Comagnetometer with a Closed-Loop Optically Aligned 87 Rb Dual-Frequency Oscillator

Zhiguo Wang, Xiang Peng, Zhiqiang Xiong, Jintao Zheng, Hui Luo, Hong Mei Guo

Published Feb 8, 2023• 3 citations
Publisher

Abstract

Comagnetometers have been widely used in fundamental research, such as tests of spin-gravity coupling and searches for permanent electric dipole moments (EDMs). Here, we report a comagnetometer that consists of simultaneous closed-loop oscillation of the $F=1$ and $F=2$ hyperfine Zeeman transitions of optically aligned ${}^{87}$$\mathrm{Rb}$ atoms. The Allan deviation of the $F=2$ and $F=1$ oscillation-frequency ratio reaches $1\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}9}$ after running continuously for 2 days, corresponding to a sensitivity of approximately $4\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}19}\phantom{\rule{0.2em}{0ex}}\mathrm{eV}$ for the measurement of the hypothetical spin-dependent gravitational energy of the proton. The long-term stability of the comagnetometer can be further improved by system-level thermal control and optimization of the experimental parameters.

DOI
10.1103/physrevapplied.19.024021

Related papers

Single-Species Atomic Comagnetometer Based on Rb 87 Atoms

Zhiguo Wang, Xiang Peng, Rui Zhang +5 more

The comagnetometer has been one of the most sensitive devices with which to test new physics related to spin-dependent interactions, but the comagnetometers based on overlapping ensembles of multiple spin species usually suffer from systematic errors due to magnetic field gradients. Here, we propose a comagnetometer based on the Zeeman transitions of the dual hyperfine levels in ground-state ^{87}Rb atoms, which shows nearly negligible sensitivity to variations of laser power and frequency, magnetic field, and magnetic field gradients. We measured the hypothetical spin-dependent gravitational energy of the proton with the comagnetometer, which is smaller than 4×10^{-18} eV, comparable to the most stringent existing constraint. Through optimizing the system parameters such as cell temperature, laser power, amplitude of driving magnetic field, as well as choosing better current source, it is possible to improve the sensitivity of the comagnetometer further.

arXiv:1812.06830•Physical Review Letters•May 13, 2020•53 citations

Herriott-cavity-assisted closed-loop Xe isotope comagnetometer

Chongyan Hao, Q.-Q. Yu, C.-Q. Yuan +2 more

We present in this paper a Herriott-cavity-assisted closed-loop Xe isotope gas comagnetometer. In this system, $^{129}\mathrm{Xe}$ and $^{131}\mathrm{Xe}$ atoms are pumped and probed by polarized Rb atoms and continuously driven by oscillating magnetic fields, whose frequencies are kept on resonance by phase-locked loops. Different from other schemes, we use a Herriott cavity to improve the Rb magnetometer sensitivity instead of the parametric modulation method, and this passive method is designed to improve the system stability while maintaining the sensitivity. This system has demonstrated an angle random walk of $0.06{}^{\ensuremath{\circ}}/{\mathrm{h}}^{1/2}$ and a bias instability of $0.2{}^{\ensuremath{\circ}}$/h (0.15 $\ensuremath{\mu}\mathrm{Hz}$) with a bandwidth of 1.5 Hz. By adding a closed-loop Rb isotope comagnetometer, we can extend this system to dual simultaneously working comagnetometers sharing the same cell. This extended system has wide applications in precision measurements, where we can simultaneously and independently measure the coupling of anomalous fields with proton spin and neutron spin.

arXiv:2105.07631•Physical Review A•May 28, 2021•22 citations

Cold-atom comagnetometry via optical control of spin states

J. -L. Zhang, W. -T. Luo, Y. A. Yang +3 more

Atomic spin-based comagnetometers are powerful tools for precision sensing and tests of fundamental physics. Compared with the widely used gas-cell comagnetometer systems, cold-atom systems offer access to much shorter distance scales and allow implementation of {optical} quantum control techniques. However, in order to realize long spin coherence times with cold atoms, it is necessary to employ diamagnetic atoms and overcome decoherence induced by light shifts. Here we demonstrate a cold-atom comagnetometer based on the nuclear spins of $^{171}$Yb (spin-1/2) and $^{173}$Yb (spin-5/2), jointly trapped in an optical lattice. Vector light shifts are suppressed by enforcing linear polarization of the lattice, while tensor shifts in $^{173}$Yb are suppressed via the use of a Schrödinger cat state. This enables simultaneous Ramsey interferometry on both isotopes with a spin coherence time of 60 s. We achieve a magnetic noise suppression factor exceeding $3\times10^4$, and determine the ratio of nuclear magnetic moments to 4 ppm precision. Our results establish a new cold-atom platform for spin-based sensing and open pathways toward quantum-enhanced searches for physics beyond the Standard Model.

physics.atom-phCross-listedarXiv:2608.13936•Nature Photonics•Aug 17, 2026•2 citations

Dual channel self-oscillating optical magnetometer

Jacopo Belfi, G. Bevilacqua, V. Biancalana +4 more

We report on a two-channel magnetometer based on nonlinear magneto-optical rotation in a Cs glass cell with buffer gas. The Cs atoms are optically pumped and probed by free running diode lasers tuned to the D2 line. A wide frequency modulation of the pump laser is used to produce both synchronous Zeeman optical pumping and hyperfine repumping. The magnetometer works in an unshielded environment, and a spurious signal from distant magnetic sources is rejected by means of differential measurement. In this regime the magnetometer simultaneously gives the magnetic field modulus and the field difference. Rejection of the common-mode noise allows for high-resolution magnetometry with a sensitivity of 2 pT/sqrt Hz. This sensitivity, in conjunction with long-term stability and a large bandwidth, makes it possible to detect water proton magnetization and its free induction decay in a measurement volume of 5 cm3.

arXiv:0812.1160•Journal of the Optical Society of America B•Apr 3, 2009•30 citations

Ultrasensitive Atomic Comagnetometer with Enhanced Nuclear Spin Coherence

Kai Wei, Tian Zhao, Xiujie Fang +8 more

Achieving high energy resolution in spin systems is important for fundamental physics research and precision measurements, with alkali-noble-gas comagnetometers being among the best available sensors. We found a new relaxation mechanism in such devices, the gradient of the Fermi-contact-interaction field that dominates the relaxation of hyperpolarized nuclear spins. We report on precise control over spin distribution, demonstrating a tenfold increase of nuclear spin hyperpolarization and transverse coherence time with optimal hybrid optical pumping. Operating in the self-compensation regime, our $^{21}\mathrm{Ne}\text{\ensuremath{-}}\mathrm{Rb}\text{\ensuremath{-}}\mathrm{K}$ comagnetometer achieves an ultrahigh inertial rotation sensitivity of $3\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}8}\text{ }\text{ }\mathrm{rad}/\mathrm{s}/{\mathrm{Hz}}^{1/2}$ in the frequency range from 0.2 to 1.0 Hz, which is equivalent to the energy resolution of $3.1\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}23}\text{ }\text{ }{\mathrm{eV}/\mathrm{Hz}}^{1/2}$. We propose to use this comagnetometer to search for exotic spin-dependent interactions involving proton and neutron spins. The projected sensitivity surpasses the previous experimental and astrophysical limits by more than 4 orders of magnitude.

arXiv:2210.09027•Physical Review Letters•Feb 10, 2023•118 citations

Self-Driven Hybrid Atomic Spin Oscillator

Erwei Li, Qianjin Ma, Guobin Liu +2 more

A self-driven hybrid atomic spin oscillator is demonstrated in theory and experiment with a vapor $\mathrm{Rb}$-$\mathrm{Xe}$ dual-spin system. The raw signal of $\mathrm{Rb}$ spin oscillation is amplified, phase-shifted, and sent back to drive the $\mathrm{Xe}$ spins coherently. By fine-tuning the driving-field strength and phase, a self-sustaining spin-oscillation signal with zero frequency shift is obtained. The effective coherence time is infinitely prolonged beyond the intrinsic coherence time of $\mathrm{Xe}$ spins, forming a hybrid atomic spin oscillator. Spectral analysis indicates that a frequency resolution of 13.1 nHz is achieved, increasing the detection sensitivity for a magnetic field. Allan-deviation analysis shows that the spin oscillator can operate in continuous-wave mode like a spin maser. The prototype spin oscillator can be easily incorporated into other hybrid spin systems and can increase the detection sensitivity of alkali-metal--noble-gas comagnetometers.

arXiv:2301.12121•Physical Review Applied•Jul 14, 2023•3 citations
Comagnetometers have been widely used in fundamental research, such as tests of spin-gravity coupling and searches for permanent electric dipole moments (EDMs). Here, we report a comagnetometer that consists of simultaneous closed-loop oscillation of the F=1F=1F=1 and F=2F=2F=2 hyperfine Zeeman transitions of optically aligned {}^{87}$$\mathrm{Rb} atoms. The Allan deviation of the F=2F=2F=2 and F=1F=1F=1 oscillation-frequency ratio reaches 1\ifmmode×\else\texttimes\fi10\ensuremath−91\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}9}1\ifmmode×\else\texttimes\fi10\ensuremath−9 after running continuously for 2 days, corresponding to a sensitivity of approximately 4\ifmmode×\else\texttimes\fi10\ensuremath−19eV4\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}19}\phantom{\rule{0.2em}{0ex}}\mathrm{eV}4\ifmmode×\else\texttimes\fi10\ensuremath−19eV for the measurement of the hypothetical spin-dependent gravitational energy of the proton. The long-term stability of the comagnetometer can be further improved by system-level thermal control and optimization of the experimental parameters.
The comagnetometer has been one of the most sensitive devices with which to test new physics related to spin-dependent interactions, but the comagnetometers based on overlapping ensembles of multiple spin species usually suffer from systematic errors due to magnetic field gradients. Here, we propose a comagnetometer based on the Zeeman transitions of the dual hyperfine levels in ground-state ^{87}Rb atoms, which shows nearly negligible sensitivity to variations of laser power and frequency, magnetic field, and magnetic field gradients. We measured the hypothetical spin-dependent gravitational energy of the proton with the comagnetometer, which is smaller than 4×10^{-18} eV, comparable to the most stringent existing constraint. Through optimizing the system parameters such as cell temperature, laser power, amplitude of driving magnetic field, as well as choosing better current source, it is possible to improve the sensitivity of the comagnetometer further.
We present in this paper a Herriott-cavity-assisted closed-loop Xe isotope gas comagnetometer. In this system, 129Xe^{129}\mathrm{Xe}129Xe and 131Xe^{131}\mathrm{Xe}131Xe atoms are pumped and probed by polarized Rb atoms and continuously driven by oscillating magnetic fields, whose frequencies are kept on resonance by phase-locked loops. Different from other schemes, we use a Herriott cavity to improve the Rb magnetometer sensitivity instead of the parametric modulation method, and this passive method is designed to improve the system stability while maintaining the sensitivity. This system has demonstrated an angle random walk of $0.06{}^{\ensuremath{\circ}}/{\mathrm{h}}^{1/2}$ and a bias instability of $0.2{}^{\ensuremath{\circ}}$/h (0.15 $\ensuremath{\mu}\mathrm{Hz}$) with a bandwidth of 1.5 Hz. By adding a closed-loop Rb isotope comagnetometer, we can extend this system to dual simultaneously working comagnetometers sharing the same cell. This extended system has wide applications in precision measurements, where we can simultaneously and independently measure the coupling of anomalous fields with proton spin and neutron spin.
Atomic spin-based comagnetometers are powerful tools for precision sensing and tests of fundamental physics. Compared with the widely used gas-cell comagnetometer systems, cold-atom systems offer access to much shorter distance scales and allow implementation of {optical} quantum control techniques. However, in order to realize long spin coherence times with cold atoms, it is necessary to employ diamagnetic atoms and overcome decoherence induced by light shifts. Here we demonstrate a cold-atom comagnetometer based on the nuclear spins of 171^{171}171Yb (spin-1/2) and 173^{173}173Yb (spin-5/2), jointly trapped in an optical lattice. Vector light shifts are suppressed by enforcing linear polarization of the lattice, while tensor shifts in 173^{173}173Yb are suppressed via the use of a Schrödinger cat state. This enables simultaneous Ramsey interferometry on both isotopes with a spin coherence time of 60 s. We achieve a magnetic noise suppression factor exceeding 3×1043\times10^43×104, and determine the ratio of nuclear magnetic moments to 4 ppm precision. Our results establish a new cold-atom platform for spin-based sensing and open pathways toward quantum-enhanced searches for physics beyond the Standard Model.
We report on a two-channel magnetometer based on nonlinear magneto-optical rotation in a Cs glass cell with buffer gas. The Cs atoms are optically pumped and probed by free running diode lasers tuned to the D2 line. A wide frequency modulation of the pump laser is used to produce both synchronous Zeeman optical pumping and hyperfine repumping. The magnetometer works in an unshielded environment, and a spurious signal from distant magnetic sources is rejected by means of differential measurement. In this regime the magnetometer simultaneously gives the magnetic field modulus and the field difference. Rejection of the common-mode noise allows for high-resolution magnetometry with a sensitivity of 2 pT/sqrt Hz. This sensitivity, in conjunction with long-term stability and a large bandwidth, makes it possible to detect water proton magnetization and its free induction decay in a measurement volume of 5 cm3.
Achieving high energy resolution in spin systems is important for fundamental physics research and precision measurements, with alkali-noble-gas comagnetometers being among the best available sensors. We found a new relaxation mechanism in such devices, the gradient of the Fermi-contact-interaction field that dominates the relaxation of hyperpolarized nuclear spins. We report on precise control over spin distribution, demonstrating a tenfold increase of nuclear spin hyperpolarization and transverse coherence time with optimal hybrid optical pumping. Operating in the self-compensation regime, our $^{21}\mathrm{Ne}\text{\ensuremath{-}}\mathrm{Rb}\text{\ensuremath{-}}\mathrm{K}$ comagnetometer achieves an ultrahigh inertial rotation sensitivity of $3\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}8}\text{ }\text{ }\mathrm{rad}/\mathrm{s}/{\mathrm{Hz}}^{1/2}$ in the frequency range from 0.2 to 1.0 Hz, which is equivalent to the energy resolution of $3.1\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}23}\text{ }\text{ }{\mathrm{eV}/\mathrm{Hz}}^{1/2}$. We propose to use this comagnetometer to search for exotic spin-dependent interactions involving proton and neutron spins. The projected sensitivity surpasses the previous experimental and astrophysical limits by more than 4 orders of magnitude.
A self-driven hybrid atomic spin oscillator is demonstrated in theory and experiment with a vapor Rb\mathrm{Rb}Rb-Xe\mathrm{Xe}Xe dual-spin system. The raw signal of Rb\mathrm{Rb}Rb spin oscillation is amplified, phase-shifted, and sent back to drive the Xe\mathrm{Xe}Xe spins coherently. By fine-tuning the driving-field strength and phase, a self-sustaining spin-oscillation signal with zero frequency shift is obtained. The effective coherence time is infinitely prolonged beyond the intrinsic coherence time of Xe\mathrm{Xe}Xe spins, forming a hybrid atomic spin oscillator. Spectral analysis indicates that a frequency resolution of 13.1 nHz is achieved, increasing the detection sensitivity for a magnetic field. Allan-deviation analysis shows that the spin oscillator can operate in continuous-wave mode like a spin maser. The prototype spin oscillator can be easily incorporated into other hybrid spin systems and can increase the detection sensitivity of alkali-metal--noble-gas comagnetometers.