原子物理
We study one-dimensional (1D) and two-dimensional (2D) Helium atoms using a new time-dependent quantum Monte Carlo (TDQMC) method. The TDQMC method employs random walkers, with a separate guiding wave attached to each walker. The ground…
Here the ionization and high harmonic generation in Hydrogen and Helium by using quantum (hydrodynamic) trajectories is analyzed theoretically. The quantum trajectories allow a self-contained treatment of the electron exchange and…
An approach to electron correlation effects in atoms that uses quantum trajectories is presented. A comparison with the exact quantum mechanical results for 1D Helium atom shows that the major features of the correlated ground state…
We present calculations of the self-energy correction to the $E1$ transition amplitudes in hydrogen-like ions, performed to all orders in the nuclear binding strength parameter. Our results for the $1s$-$2p_{1/2}$ transition for the…
We present a recently established setup for laser spectroscopy at CRYRING@ESR at the GSI Helmholtz Centre for Heavy Ion Research. Here, laser spectroscopy can be performed on stored and cooled ion bunches and coasting beams. First spectra…
In this paper we use sets of de Broglie-Bohm trajectories to describe the quantum correlation effects which take place between the electrons in helium atom due to exchange and Coulomb interactions. A short-range screening of the Coulomb…
We present an approach for in situ dynamic four-dimensional (4D=3D space + 1D time) laser induced strong field ionization tomography, particularly suited for measuring far-from-equilibrium systems, such as supersonic and hypersonic pulsed…
We report a measurement of the absolute frequency of the 1S0-3P0 transition in the 171Yb optical lattice clock at KRISS (KRISS-Yb1) for 14 months, which was referenced to the SI second by primary and secondary standards worldwide via TAI…
The binding energies of the five bound rotational levels $J=0-4$ in the highest vibrational level $v=14$ in the X$^1\Sigma_g^+$ ground electronic state of H$_2$ were measured in a three-step ultraviolet-laser experiment. Two-photon…
Here the recently proposed time-dependent quantum Monte Carlo method is applied to three dimensional para- and ortho-helium atoms subjected to an external electromagnetic field with amplitude sufficient to cause significant ionization. By…
Accurate lifetime measurements of excited states of highly charged ions (HCIs) are essential for advancing diagnostics in both laboratory and astrophysical plasmas, especially in the X-ray regime. The Hanle effect, which utilizes external…
A method is presented for the improved calculation of super-shell partition functions which include the repulsive electron-electron interaction energy terms in the Boltzmann factor. Heretofore these interaction terms were approximately…
Magic trapping of ground and Rydberg states, which equalizes the AC Stark shifts of these two levels, enables increased ground-to-Rydberg state coherence times. We measure via photon storage and retrieval how the ground-to-Rydberg state…
An enhanced mechanism is proposed for the large-amplitude-motion-induced parity-violating frequency by integrating the exact quantum dynamics method with the relativistic electronic structure theory. The torsional wavefunctions and PV…
We describe the short-term frequency stability characterization of external-cavity diode lasers stabilized onto the 6S$_{1/2}$-7P$_{1/2}$ transition of Cs atom at 459 nm, using a microfabricated vapor cell. The laser beatnote between two…
The features of Doppler-free resonances detected by probing the $^{133}$Cs atom $6S_{1/2}-7P_{3/2}$ transition at 456 nm in a nanometric-thick vapor layer are investigated. The matrix element of this transition is about 11 times smaller…
We have studied experimentally and theoretically the impact of various parameters on the characteristics of signals from a two-axis Hanle magnetometer based on the Cs D$_1$ transition illuminated by linearly polarized pump and probe beams…
We present an experimental method for the characterization of the kinetic energies of ions confined in a 22-pole radio frequency trap by inducing a small potential barrier using the surrounding ring electrodes, allowing the selective…
We demonstrate an optical clock based on Ramsey-Bord\'e interferometry in a laser-cooled ${}^{40}$Ca beam. The mean velocity is reduced by an order of magnitude relative to a thermal beam and the transverse temperature approaches the…
We report initial research to develop a compact and practical primary thermometer based on Doppler broadening thermometry (DBT). The DBT sensor uses an intrinsic property of thermalized atoms, namely, the Doppler width of a spectral line…