ABSTRACT
We report on observations of coherent, sustained oscillations in the absorption of continuous-wave light at 388 nm that excites the 6S1/2 â 8P3/2 transition in cesium (Cs) vapor. The oscillation frequency is close to the spacing of hyperfine levels of the 8P3/2 level that are excited simultaneously by the 388 nm field. We observe a threshold behavior of the oscillation amplitude with pump power and suggest that the effect is associated with infrared directional emission due to amplified spontaneous emission (ASE) from the 8P3/2 â 8S1/2 transition that is assisted by retro-reflections from cell windows. The effect may be used to probe a lasing process in an atomic vapor, by checking the temporal properties of the pump field transmitted through the vapor.
ABSTRACT
A possible implication of an ultralight dark matter field interacting with the standard model degrees of freedom is oscillations of fundamental constants. Here, we establish direct experimental bounds on the coupling of an oscillating ultralight dark matter field to the up, down, and strange quarks and to the gluons, for oscillation frequencies between 10 and 10^{8} Hz. We employ spectroscopic experiments that take advantage of the dependence of molecular transition frequencies on the nuclear masses. Our results apply to previously unexplored frequency bands and improve on existing bounds at frequencies >5 MHz. We also improve on the bounds for coupling to the electromagnetic field and the electron field, in particular spectral windows. We identify a sector of ultralight dark matter and standard model coupling space where the bounds from equivalence principle tests may be challenged by next-generation experiments of the present kind.
ABSTRACT
We report measurements of isotope shifts for the five spinless Yb isotopes on the 6s^{2} ^{1}S_{0}â5d6s ^{1}D_{2} transition using Doppler-free two-photon spectroscopy. We combine these data with existing measurements on two transitions in Yb^{+} [Counts et al. Phys. Rev. Lett. 125, 123002 (2020)PRLTAO0031-900710.1103/PhysRevLett.125.123002], where deviation from King-plot linearity showed hints of a new bosonic force carrier at the 3σ level. The combined data strongly reduce the significance of the new-physics signal. We show that the observed nonlinearity in the joint Yb/Yb^{+} King-plot analysis can be accounted for by the deformation of the Yb nuclei.
ABSTRACT
Among the prominent candidates for dark matter are bosonic fields with small scalar couplings to the standard-model particles. Several techniques are employed to search for such couplings, and the current best constraints are derived from tests of gravity or atomic probes. In experiments employing atoms, observables would arise from expected dark-matter-induced oscillations in the fundamental constants of nature. These studies are primarily sensitive to underlying particle masses below 10^{-14} eV. We present a method to search for fast oscillations of fundamental constants using atomic spectroscopy in cesium vapor. We demonstrate sensitivity to scalar interactions of dark matter associated with a particle mass in the range 8×10^{-11} to 4×10^{-7} eV. In this range our experiment yields constraints on such interactions, which within the framework of an astronomical-size dark matter structure are comparable with, or better than, those provided by experiments probing deviations from the law of gravity.
ABSTRACT
We report on the studies of simultaneous continuous-wave mirrorless lasing on multiple optical transitions, realized by pumping hot cesium (Cs) vapor with laser light resonant with the 6S1/2â8P3/2 transition. The multiplicity of the decay paths for the excited atoms to their ground state is responsible for the emergence of lasing in a number of transitions, observed here in at least seven wavelengths in the infrared and at two wavelengths in the blue. We study the properties of the fields generated in the Cs vapor such as optical power, directionality, and optical linewidth.
