Related papers: Blackbody radiation shift in the Sr optical atomic…
The ac Stark shift (or light shift) of the 6$^{2}$S$_{1/2}$ (F $=$ 3 $\leftrightarrow $ 4) transition in $^{133}$Cs, as observed through coherent population trapping under pulsed excitation, is measured using a $^{133}$Cs gas cell and the…
We have measured the isotope shift of the narrow quadrupole-allowed 5 2S1/2 - 4 2D5/2 transition in 86Sr+ relative to the most abundant isotope 88Sr+. This was accomplished using high-resolution laser spectroscopy of individual trapped…
We present an assessment of the (6s^{2})1S0 -> (6s7s)3P0 clock transition frequency in 199Hg with an uncertainty reduction of nearly three orders of magnitude and demonstrate an atomic quality factor, Q, of ~10^(14). The 199Hg atoms are…
Accurate measurements of different transition frequencies between atomic levels of the electronic and hyperfine structure over time are used to investigate temporal variations of the fine structure constant $\alpha$ and the…
The optical (BVRI) and radio (8.4 GHz) light curves of S5 1803+784 on a time span of nearly 6 years are presented and discussed. The optical light curve showed an overall variation greater than 3 mag, and the largest changes occured in…
We studied the variability of the linear polarization and brightness of the $\gamma$-ray binary LS I +61 303. High-precision BVR photopolarimetric observations were carried out with the Dipol-2 polarimeter on the 2.2 m remotely controlled…
We report an uncertainty evaluation of an optical lattice clock based on the $^1S_0\leftrightarrow^3P_0$ transition in the bosonic isotope $^{174}$Yb by use of magnetically induced spectroscopy. The absolute frequency of the…
We investigated the coherence of spin-polarized ^{87}Sr atoms trapped in a light-shift-free one-dimensional optical lattice during their interaction with a clock laser on the ^1S_0-^3P_0 transition. Collapses and revivals appeared for more…
Optical lattice clocks have the potential for extremely high frequency stability owing to the simultaneous interrogation of many atoms, but this precision may come at the cost of systematic inaccuracy due to atomic interactions.…
A theory of dynamic polarizability for trapping relevant states of Sr$^+$ is presented here when the ions interact with a focused optical vortex. The coupling between the orbital and spin angular momentum of the optical vortex varies with…
One of the directly measured quantities which are used in monitoring the orbital motions of many of the S stars revolving around the Supermassive Black Hole (SMBH) in the Galactic Center (GC) is their radial velocity (RV) $V$ obtained with…
We study ultranarrow $5s_{1/2}$ - $4f_{5/2}$ transitions in Nd$^{13+}$ and Sm$^{15+}$ and demonstrate that they lie in the optical region. The transitions are insensitive to external perturbations. At the same time they are sensitive to the…
We perform spectroscopy on the optical dipole transitions 5s5p $^3$P$_2$ - 5s$n$d $^3$D$_{1,2,3}$, $n \in (5,6)$, for all stable isotopes of atomic strontium. We develop a new spectroscopy scheme, in which atoms in the metastable $^3$P$_2$…
We have monitored the BL Lacertae object S5 0716+714 in the optical bands during 2012 January and February with long time spans on intraday timescales ($>$5 hr) and high time resolutions. During this monitoring period, the object shows…
Haystack and Owens Valley Radio Observatory (OVRO) observations recently revealed strong, intermittent, sinusoidal total flux-density variations that maintained coherence between 1975 and 2021 in the blazar PKS 2131$-$021 ($z=1.283$). This…
We present a numerical method for extrapolating polarizability measurements to dc as done in the assessment of blackbody radiation shifts for ion-based clocks. The method explicitly accounts for the frequency dependence of relevant atomic…
We report the direct frequency measurement of the visible 5s$^2$ $^1$S$_0$-5s 5p$^3$P$_1$ intercombination line of strontium that is considered a possible candidate for a future optical frequency standard. The frequency of a…
We optically excite the electronic state $3s3p~^3P_{0}$ in $^{24}$Mg atoms, laser-cooled and trapped in a magic-wavelength lattice. An applied magnetic field enhances the coupling of the light to the otherwise strictly forbidden transition.…
The polarized and total flux of the BL Lac object PKS 2155-304 were monitored intensively and simultaneously in the optical UBVRI bands with the Turin photopolarimeter at the CASLEO 2.15 m telescope during 4 campaigns in June, August,…
We report rapid optical variability for the blazar S5 0716+71 during 2010 March 08-10 & 19-20 in the CCD observations made from Mt.Abu Infrared Observatory. The light curves are constructed for the duration longer than 3-hours each night,…