Search for Ultralight Dark Matter with Spectroscopy of Radio-Frequency Atomic Transitions.

The effects of scalar and pseudoscalar ultralight bosonic dark matter (UBDM) were searched for by comparing the frequency of a quartz oscillator to that of a hyperfine-structure transition in ^{87}Rb, and an electronic transition in ^{164}Dy. We constrain linear interactions between a scalar UBDM field and standard-model (SM) fields for an underlying UBDM particle mass in the range 1×10^{-17}-8.3×10^{-13} eV and quadratic interactions between a pseudoscalar UBDM field and SM fields in the range 5×10^{-18}-4.1×10^{-13} eV. Within regions of the respective ranges, our constraints on linear interactions significantly improve on results from previous, direct searches for oscillations in atomic parameters, while constraints on quadratic interactions surpass limits imposed by such direct searches as well as by astrophysical observations.

Improved Bounds on Ultralight Scalar Dark Matter in the Radio-Frequency Range.

We present a search for fundamental constant oscillations in the range 20 kHz-100 MHz that may arise within models for ultralight dark matter (UDM). Using two independent optical-spectroscopy apparatuses, we achieve up to ×1000 greater sensitivity in the search relative to previous work [D. Antypas et al., Phys. Rev. Lett. 123, 141102 (2019).PRLTAO0031-900710.1103/PhysRevLett.123.141102]. We report no observation of UDM and thus constrain respective couplings to electrons and photons within the investigated UDM particle mass range 8×10^{-11}-4×10^{-7} eV. The constraints significantly exceed previously set bounds from atomic spectroscopy and, as we show, may surpass in future experiments those provided by equivalence-principle (EP) experiments in a specific case regarding the combination of UDM couplings probed by the EP experiments.

On the Possibility of Miniature Diamond-Based Magnetometers Using Waveguide Geometries.

We propose the use of a diamond waveguide structure to enhance the sensitivity of magnetometers relying on the detection of the spin state of nitrogen-vacancy ensembles in diamond by infrared optical absorption. An optical waveguide structure allows for enhanced optical path-lengths avoiding the use of optical cavities and complicated setups. The presented design for diamond-based magnetometers enables miniaturization while maintaining high sensitivity and forms the basis for magnetic field sensors applicable in biomedical, industrial and space-related applications.

Lineshape-asymmetry elimination in weak atomic transitions driven by an intense standing wave field.

Owing to the ac-Stark effect, the lineshape of a weak optical transition in an atomic beam can become significantly distorted when driven by an intense standing wave field. We use an Yb atomic beam to study the lineshape of the 6s2S10→5d6sD31 transition, which is excited with light circulating in a Fabry-Perot resonator. We demonstrate two methods to avoid the distortion of the transition profile. Of these, one relies on the operation of the resonator in multiple longitudinal modes, and the other in multiple transverse modes.