相关论文: Electric-field induced helium-helium resonances
Recent studies have shown direct ion heating (vashistha2020new,Juneja_2023) by lasers EM (Electromagnetic) wave interacting with a plasma threaded by an external uniform magnetic field. The EM wave frequency was near the lower hybrid (LH)…
The paper summarizes elements of theories and computational methods that we have constructed and applied over the years for the nonperturbative solution of many electron problems, in the absence or presence of strong external fields,…
On the basis of variational method we study energy levels of pionic helium $(\pi-e-He)$ and kaonic helium $(K-e-He)$ with an electron in ground state and a meson in excited state with principal and orbital quantum numbers $n\sim l+1\sim…
The electric dipole polarizabilities of $^3$H, $^3$He, and $^4$He are calculated directly using the Schr\"odinger equation with the latest generation of two- and three-nucleon interactions. These polarizabilities are necessary in order to…
Models of the solar transition region made from lines other than those of helium cannot account for the strength of the helium lines. However, the collisional excitation rates of the helium resonance lines are unusually sensitive to the…
Two new low-lying $^6$He levels at excitation energies of about 2.4 and 2.9 MeV were observed in the experimental investigation of the p-$\alpha$ coincidence spectra obtained by the $^3$H($^4$He,p$\alpha$)2n four-body reaction at $E_{\rm…
Nuclear interactions play a key role for the stability of atomic nuclei and stellar environments. Successful parametrization and models of these interactions, developed in the last decades, accurately reproduce all the proton and neutron…
We have examined the profile of an isolated autoionizing resonance driven by a pulse of short duration and moderately strong field. The analysis has been based on stochastic differential equations governing the time evolution of the density…
The two-neutron RPA model has been used to describe helium isotopes with N (the neutron number) = 4, 6, 7, 8 in their ground and excited states. The properties of all these isotopes are given by a single system of equations so that their…
We derive from first principles the existence of a low-frequency plasmon in a strongly coupled three-dimensional homogeneous electron gas (HEG). From its dispersion and its satisfaction of the 3rd frequency sum rule we identify it with the…
Spin manipulation in coupled quantum dots is of interest for quantum information applications. Control of the exchange interaction between electrons and holes via an applied electric field may provide a promising technique for such spin…
We predict the formation of intravalley controllable trions in buckled two-dimensional (2D) materials such as silicene, germanene, and stanene monolayers in an external electric field. Performing a study within the framework of a…
In solar EUV spectra the He I and He II resonance lines show unusual behaviour and have anomalously high intensities compared with other transition region lines. The formation of the helium resonance lines is investigated through extensive…
The "soft dipole" E1 strength function is calculated for the transition from the $^{6}$He $0^+$ ground state to the $1^-$ continuum $^{4}$He+$n$+$n$. The calculations were performed within the hyperspherical harmonics formalism. The…
We consider highly radiating ultra-relativistic electrons in a strong external electromagnetic field. High intensity radiative losses and consequent $e^+e^-$-pair production, appearing in the frame of quantum electrodynamics, determine…
In this work we study the problem of a charged particle, bound in a harmonic-oscillator potential, being excited by the Coulomb field from a fast charged projectile. Based on a classical solution to the problem and using the squeezed-state…
Electric fields in a plasma that conducts a high-current pulse are measured as a function of time and space. The experiment is performed using a coaxial configuration, in which a current rising to 160 kA in 100 ns is conducted through a…
The resonance states of $^{4}H$, $^{4}He$ and $^{4}Li$, embedded in the three-cluster $d+N+N$ continuum, are investigated within a three-cluster model. The model treats the Pauli principle exactly and incorporates the Faddeev components for…
The photoionization of a helium atom by short intense laser pulses is studied theoretically in the vicinity of the $2s2p\,^1P$ doubly-excited state with the intention to investigate the impact of the intensity and duration of the exciting…
The potential energy surface (PES) describing the interactions between $\mathrm{Li_{2}(^{1}\Sigma_{u}^{+})}$ and $\mathrm{^{4}He}$ and an extensive study of the energies and structures of a set of small clusters, $\mathrm{Li_{2}(He)_{n}}$,…