Origin, Evolution, and Imaging of Vortices in Atomic Processes

Abstract

Vortices are usually associated with systems containing large numbers of particles. Of particular topical interest though are those formed within atomic-scale wave functions and observed in macroscopic systems such as superfluids and quantum condensates. We uncover them here in one of the most fundamental quantum systems consisting of just one electron and two protons. Moreover, the results of novel simulations of the dynamics of this system reveal previously unknown mechanisms of angular momentum transfer and new ways to image atomic-scale quantized vortices at macroscopic distances. Probing of vortices and vortex-driven dynamics in quantum systems is thereby illustrated.

Multistart spiral electron vortices in ionization by circularly polarized UV pulses

“…Perturbation theory (PT) is used to analyze the patterns exhibited by the momentum distributions. Within our PT formalism, a connection between our electron matter-wave vortices and vortices in a physical process associated with zeros in the scattering wave function [12][13][14][15][16][17][18][19][20] has been established [8]. In contrast to dynamical vortex patterns, which depend upon the transition amplitudes of the process considered, the vortex patterns in the ionized electron momentum distributions we predict here (and in Ref.…”

Electron Vortices in Photoionization by Circularly Polarized Attosecond Pulses

“…The connection between a zero of the probability distribution and a zero of the system wave function is given by the so-called "imaging theorem" [21]. Velocity field vortices have been intensively studied for collision processes involving ionization of atoms and molecules by electron impact [21][22][23], proton impact [24], positron impact [25], ion impact [26], and both antiproton and photon impact [27]. Also, vortices associated with population transfers to excited and continuum states have been studied in the electron probability density of an atom subject to short linearly-polarized electric fields [27,28].…”

Recent Applications Of The Lattice, Time-Dependent Schrödinger Equation Approach For Ion-Atom Collisions

“…To go beyond this limitation, we have very recently developed a new approach, the regularized LTDSE (RLTDSE) method [14], in order to propagate the solution to distances where we are assured that the electronic probability distribution is comparable to that which would be observed experimentally. In so doing, we have unexpectedly observed vortices in the electronic wavefunction [15]. We have also found that certain of these vortices, being born in the collision, surprisingly survive to asymptotic distances in the electronic continuum and may thus be observable in experiments.…”

“…As described previously [15,16], enabled by RLTDSE calculations, we examined the timedependence of the electronic wavefunction (for proton-hydrogen collisions at 5 keV) throughout the evolution from near the collision to large internuclear separations, and noticed, unexpectedly, that deep minima existed when the nuclei were close, some of which persisted to the largest final distances considered. After examining the electronic probability current, we confirmed that these deep minima were vortices and were in fact quantized.…”