2 research outputs found
Cesium atoms in cryogenic argon matrix
This paper presents both experimental and theoretical investigations into the
spectroscopy of dilute cesium (Cs) atoms within a solid argon (Ar) matrix at
cryogenic temperatures. This system is relevant for matrix isolation
spectroscopy and in particular for recently proposed methods for investigating
phenomena that extend beyond the standard model of particle physics. We record
absorption spectra at various deposition temperatures and examine the evolution
of these spectra post-deposition with respect to temperature changes.
Taking advantage of Cs-Ar and Ar-Ar pairwise interaction potentials, we
conduct a stability study of trapping sites, which indicates a preference for
T (tetrahedral, 4 vacancies) and O (cubic, 6 vacancies)
symmetries. By implementing a mean-field analysis of the long-range
Cs(6s,6p)-Ar-Ar triple dipole interaction, combined with a
temperature-dependent shift in zero point energy, we propose effective
Cs(6s,6p)-Ar pairwise potentials. Upon integrating these pairwise potentials
with spin-orbit coupling, we achieve a satisfactory agreement between the
observed and simulated absorption line positions. The observed line broadening
is reasonably well reproduced by a semi-classical thermal Monte Carlo approach
based on Mulliken-type differences between excited and ground potential curves.
Additionally, we develop a simple, first-order crystal field theory featuring
only 6 interaction mode coordinates. It uses the reflection approximation and
incorporates quantized (phonon) normal modes. This produces a narrow triplet
structure but not the observed amount of splitting
CPT and Lorentz symmetry tests with hydrogen using a novel in-beam hyperfine spectroscopy method applicable to antihydrogen experiments
We present a Rabi-type measurement of two ground-state hydrogen hyperfine transitions performed in two opposite external magnetic field directions. This puts first constraints at the level of 2.3 × 10^{−21} GeV on a set of coefficients of the Standard Model Extension, which were not measured by previous experiments. Moreover, we introduce a novel method, applicable to antihydrogen hyperfine spectroscopy in a beam, that determines the zero-field hyperfine transition frequency from the two transitions measured at the same magnetic field. Our value, ν_0 = 1.420 405 751 63(63) GHz, is in agreement with literature at a relative precision of 0.44 ppb. This is the highest precision achieved on hydrogen in a beam, improving over previous results by a factor of 6