Related papers: Cold atom-dimer reaction rates with $^4$He, $^{6,7…
The formation/binding energetics and length scales associated with the interaction between He atoms and grain boundaries in BCC alpha-Fe was explored. Ten different low Sigma grain boundaries from the <100> and <110> symmetric tilt grain…
The rate at which helium ($^4$He) and deuterium ($d$) fuse together to produce lithium-6 ($^6$Li) and a $\gamma$ ray, $^4$He$(d,\gamma)^6$Li, is a critical puzzle piece in resolving the roughly three orders of magnitude discrepancy between…
Cold quantum gases, when acted upon by electromagnetic fields, can give rise to samples where isolated atoms coexist with dimers or trimers, which raises the question of the interactions between these various constituents. Here we perform…
Correlations of back-to-back coincident $\Lambda d$ and $\Lambda t$ pairs from the stopped $K^-$ reaction on $^4$He had been investigated, thereby $\Lambda d$ and $\Lambda t$ branches of non-mesonic three- and four-nucleon absorption…
We study dark matter scattering off ${}^4$He and other light nuclei using chiral effective field theory. We consider scalar DM interactions and include both one- and two-nucleon scattering processes. The DM interactions and nuclear wave…
We aim to show the importance of non-elastic excitation and deexcitation processes in $\textrm{He}^{*}(n)+ \textrm{He}(1s^{2})$ collisions with the principal quantum number $n \ge 3$ for helium-rich white dwarf atmospheres. We compare the…
This work is concerned with the theoretical study of nuclear reactions between light charged ions at incident energies around and below the reactants Coulomb barrier, with a focus on the energy range of astrophysical interest for Big Bang…
In several experiments with ultracold trapped atoms, a narrow loss feature has been observed near an {\it atom-dimer resonance}, at which there is an Efimov trimer at the atom-dimer threshold. The conventional interpretation of these loss…
We studied a novel cooling method, in which $^3$He and $^4$He are mixed at the $^4$He crystallization pressure at temperatures below $0.5\,\mathrm{mK}$. We describe the experimental setup in detail, and present an analysis of its…
We implement manifestly microscopic many-body methods to study the dynamics of atomic impurities in a host quantum fluid, specifically $^4$He. Our investigations are motivated by experiments of muonium atoms within $^4$He with the goal of…
We study an excited atom-polar molecular ion chemical reaction (Ca$^*$ + BaCl$^+$) at low temperature by utilizing a hybrid atom-ion trapping system. The reaction rate and product branching fractions are measured and compared to model…
We perform a theoretical analysis of atomic four-wave mixing via a collision of two Bose-Einstein condensates of metastable helium atoms, and compare the results to a recent experiment. We calculate atom-atom pair correlations within the…
Motivated by recent experimental investigations of Cs-Cs-Li Efimov resonances, this work theoretically investigates the few-body properties of $N-1$ non-interacting identical heavy bosons, which interact with a light impurity through a…
Ultracold chemical reactions of weakly bound triplet-state alkali-metal dimer molecules have recently attracted much experimental interest. We perform rigorous quantum scattering calculations with a new $ab\, initio$ potential energy…
We present a new, mathematically rigorous, method suitable for bound state and scattering processes calculations for various three atomic or molecular systems where the underlying forces are of a hard-core nature. We employed this method to…
We investigate the finite nuclear mass corrections in the helium atom in order to resolve a significant disagreement between the $2^3S - 2^3P$ and $2^3S - 2^1S$ transition isotope shifts. These two transitions lead to discrepant results for…
We report the results of a detailed calculation of nucleon weak interactions relevant for the neutron to proton density ratio at the onset of primordial nucleosynthesis. Radiative electromagnetic corrections, finite nucleon mass terms,…
To describe the grazing scattering of keV atoms at surface, a new quantum binary collision model have been proposed where the dynamical properties of the surface atoms are considered via the wave-function of the local Debye harmonic…
We critically examine the current status of theoretical calculations of the energies, the fine structure, and the isotope shift of the lowest-lying states of helium, searching for unresolved discrepancies with experiments. Calculations are…
Rubidium dimers residing on the surface of He nanodroplets are doubly ionized by an intense fs laser pulse leading to fragmentation into a pair of $\mathrm{Rb^+}$ ions. We show that the kinetic energy of the $\mathrm{Rb^+}$ fragment ions…