A quantum model for calculating the combined Stark and Zeeman effects of simultaneously applied electric and magnetic fields is presented. Our focus here is on atoms with hyperfine structure, such as Cesium. Matrix representations of the Stark, Zeeman, and hyperfine interaction operators are constructed using angular momentum theory and spherical tensor algebra. Matrix elements are evaluated in order to determine the energy-level dependence on the applied fields and reveal intriguing state dynamics in both parallel and orthogonal electric and magnetic fields. The fundamental physics is relevant for an advanced undergraduate or graduate quantum mechanics course.
We present experimental and theoretical studies of coherent excitation of magnetic sublevels in nD states of cesium that cross in an external electric field. Coherent excitation of mFmagnetic sublevels of hyperfine F levels with DeltamF= plusmn2 leads to resonances in the linearly polarized laser induced fluorescence (LIF), while coherent excitation of magnetic sublevels with DeltamF= plusmn1 leads to alignment to orientation conversion (AOC). From the resonance signals we were able to measure atomic constants, such as the hyperfine constant A and the tensor polarizability alpha2(Auzinsh et al., 2006). AOC involves the deformation of the spatial distribution of an atom's angular momentum and is of interest as a background in certain types of experiments that search for a permanent electric dipole moment (EDM) of the electron.
We discuss experimental and theoretical studies of coherent excitation of magnetic sublevels in nD states of cesium that cross in an external electric field. Crossings of mF magnetic sublevels of hyperfine F levels with &Dgr;mF = ±2 lead to resonances in the linearly polarized laser induced fluorescence, while crossings with &Dgr;mF = ±1 lead to resonances in the circularly polarized laser induced fluorescence. These resonances can be exploited to observe alignment to orientation conversion. From the level crossing signals it is possible to measure atomic properties, such as the tensor polarizability &agr;2 and the hyperfine constant A. Alignment to orientation conversion involves the deformation of the spatial distribution of an atom's angular momentum.
We have observed the crossing of the atomic hydrogen levels ${\ensuremath{\beta}}_{B}(2{S}_{\frac{1}{2}}, {m}_{J}=\ensuremath{-}\frac{1}{2}, {m}_{I}=\ensuremath{-}\frac{1}{2})$ and ${e}_{B}(2{P}_{\frac{1}{2}}, {m}_{J}=+\frac{1}{2}, {m}_{I}=\ensuremath{-}\frac{1}{2})$ near 605 G. A new atomic-beam method is used. H atoms are excited to the metastable
2S state by electron bombardment. The $2S({m}_{J}=\ensuremath{-}\frac{1}{2})$ state is quenched in the bombardment region. The
2S(mJ=+21) beam passes through a zero-field region where
31 of it is converted to the single hyperfine level ${\ensuremath{\beta}}_{B}$. The ${\ensuremath{\beta}}_{B}$ atoms enter a uniform magnetic field parallel to the beam. With no externally applied electric field, 92% of them reach the detector. When we apply an electrostatic field of about 0.7 V/cm perpendicular to the beam, the ${\ensuremath{\beta}}_{B}$ atoms are strongly quenched near the ${\ensuremath{\beta}}_{B}\ensuremath{-}{e}_{B}$ crossing point. Observed quenching agrees with the Bethe-Lamb theory of the
2S lifetime in external fields. We measure magnetic field by the nuclear magnetic resonance frequency of protons in water. Natural asymmetry and minor experimental corrections reduce the observed center of the ${\ensuremath{\beta}}_{B}\ensuremath{-}{e}_{B}$ quenching resonance by 1 part in
104. The corrected ${\ensuremath{\beta}}_{B}\ensuremath{-}{e}_{B}$ crossing occurs at 2577.57\ifmmode\pm\else\textpm\fi{}0.25 kc/sec, proton nmr in water. From this, we calculate the Lamb shift
S in H,
n=2. With a diamagnetic shielding correction, and the accurately known
2S hyperfine interval, we get $\mathcal{S}=1058.07\ifmmode\pm\else\textpm\fi{}0.10$ Mc/sec. This disagrees with $\mathcal{S}=1057.77\ifmmode\pm\else\textpm\fi{}0.10$ Mc/sec from the Lamb experiments.
We investigate the impact of combined electric and magnetic fields on the structure of ultralong-range polar Rydberg molecules. Our focus is hereby on the parallel as well as the crossed field configuration, taking into account both the s -wave and p -wave interactions of the Rydberg electron and the neutral ground state atom. We show the strong impact of the p -wave interaction on the ultralong-range molecular states for a pure B -field configuration. In the presence of external fields, the angular degrees of freedom acquire vibrational character, and we encounter two- and three-dimensional oscillatory adiabatic potential energy surfaces for the parallel and crossed field configuration, respectively. The equilibrium configurations of local potential wells can be controlled via the external field parameters for both field configurations depending on the specific degree of electronic excitation. This allows us to tune the molecular alignment and orientation. The resulting electric dipole moment is in the order of several kDebye, and the rovibrational level spacings are in the range of 2– . Both properties are analyzed with varying field strengths.