We report the results of an experimental search for ultralight axionlike dark matter in the mass range 162-166 neV. The detection scheme of our Cosmic Axion Spin Precession Experiment is based on a ...precision measurement of ^{207}Pb solid-state nuclear magnetic resonance in a polarized ferroelectric crystal. Axionlike dark matter can exert an oscillating torque on ^{207}Pb nuclear spins via the electric dipole moment coupling g_{d} or via the gradient coupling g_{aNN}. We calibrate the detector and characterize the excitation spectrum and relaxation parameters of the nuclear spin ensemble with pulsed magnetic resonance measurements in a 4.4 T magnetic field. We sweep the magnetic field near this value and search for axionlike dark matter with Compton frequency within a 1 MHz band centered at 39.65 MHz. Our measurements place the upper bounds |g_{d}|<9.5×10^{-4} GeV^{-2} and |g_{aNN}|<2.8×10^{-1} GeV^{-1} (95% confidence level) in this frequency range. The constraint on g_{d} corresponds to an upper bound of 1.0×10^{-21} e cm on the amplitude of oscillations of the neutron electric dipole moment and 4.3×10^{-6} on the amplitude of oscillations of CP-violating θ parameter of quantum chromodynamics. Our results demonstrate the feasibility of using solid-state nuclear magnetic resonance to search for axionlike dark matter in the neV mass range.
Numerous observations suggest that there exist undiscovered beyond‐the‐standard‐model particles and fields. Because of their unknown nature, these exotic particles and fields could interact with ...standard model particles in many different ways and assume a variety of possible configurations. Here, an overview of the global network of optical magnetometers for exotic physics searches (GNOME), the ongoing experimental program designed to test a wide range of exotic physics scenarios, is presented. The GNOME experiment utilizes a worldwide network of shielded atomic magnetometers (and, more recently, comagnetometers) to search for spatially and temporally correlated signals due to torques on atomic spins from exotic fields of astrophysical origin. The temporal characteristics of a variety of possible signals currently under investigation such as those from topological defect dark matter (axion‐like particle domain walls), axion‐like particle stars, solitons of complex‐valued scalar fields (Q‐balls), stochastic fluctuations of bosonic dark matter fields, a solar axion‐like particle halo, and bursts of ultralight bosonic fields produced by cataclysmic astrophysical events such as binary black hole mergers are surveyed.
The global network of optical magnetometers for exotic physics searches (GNOME) is a worldwide network of shielded atomic magnetometers and comagnetometers designed to search for spatially and temporally correlated signals from exotic fields of astrophysical origin. This paper surveys a variety of exotic physics scenarios which the GNOME collaboration is investigating.
We present a method which allows for the extraction of physical quantities directly from zero- to ultralow-field nuclear magnetic resonance (ZULF NMR) data. A numerical density matrix evolution is ...used to simulate ZULF NMR spectra of several molecules in order to fit experimental data. The method is utilized to determine the indirect spin-spin couplings (\(J\)-couplings) in these, which is achieved with precision of \(10^{-2}\)--\(10^{-4}\) Hz. The simulated and measured spectra are compared to earlier research. Agreement and precision improvement for most of the \(J\)-coupling estimates are achieved. The availability of an efficient, flexible fitting method for ZULF NMR enables a new generation of precision-measurement experiments for spin-dependent interactions and physics beyond the Standard Model.
We report the results of an experimental search for ultralight axion-like dark matter in the mass range 162 neV to 166 neV. The detection scheme of our Cosmic Axion Spin Precession Experiment ...(CASPEr) is based on a precision measurement of \(^{207}\)Pb solid-state nuclear magnetic resonance in a polarized ferroelectric crystal. Axion-like dark matter can exert an oscillating torque on \(^{207}\)Pb nuclear spins via the electric-dipole moment coupling \(g_d\), or via the gradient coupling \(g_{\text{aNN}}\). We calibrated the detector and characterized the excitation spectrum and relaxation parameters of the nuclear spin ensemble with pulsed magnetic resonance measurements in a 4.4 T magnetic field. We swept the magnetic field near this value and searched for axion-like dark matter with Compton frequency within a 1 MHz band centered at 39.65 MHz. Our measurements place the upper bounds \(|g_d|<9.5\times10^{-4}\,\text{GeV}^{-2}\) and \(|g_{\text{aNN}}|<2.8\times10^{-1}\,\text{GeV}^{-1}\) (95% confidence level) in this frequency range. The constraint on \(g_d\) corresponds to an upper bound of \(1.0\times 10^{-21}\,\text{e}\cdot\text{cm}\) on the amplitude of oscillations of the neutron electric dipole moment, and \(4.3\times 10^{-6}\) on the amplitude of oscillations of CP-violating \(\theta\) parameter of quantum chromodynamics. Our results demonstrate the feasibility of using solid-state nuclear magnetic resonance to search for axion-like dark matter in the nano-electronvolt mass range.
We use magnetic-field-dependent features in the photoluminescence of negatively charged nitrogen-vacancy centers to measure magnetic fields without the use of microwaves. In particular, we present a ...magnetometer based on the level anti-crossing in the triplet ground state at 102.4 mT with a demonstrated noise floor of 6 nT/\(\sqrt{\text{Hz}}\), limited by the intensity noise of the laser and the performance of the background-field power supply. The technique presented here can be useful in applications where the sensor is placed closed to conductive materials, e.g. magnetic induction tomography or magnetic field mapping, and in remote-sensing applications since principally no electrical access is needed.
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