Atoms

Probing Atomic ‘Quantum Grating’ by Collisions with Charged Particles

Bennaceur Najjari, Shaofeng Zhang, X. Ma, Alexander B Voitkiv

Published Nov 1, 2022• 0 citations

Abstract

The wave function of an atom, which passed through a diffraction grating, is characterized by a regular space structure. Correspondingly, the interaction of another particle with this atom can be viewed as scattering on an ‘atomic quantum grating’ made of just a single atom. Probing this ‘grating’ by collisions with a charged projectile reveals few-body interference phenomena caused by the coherent contributions of its ‘slits’ to the transition amplitude (the superposition principle) and quantum entanglement of the particles involved. In particular, the spectra of electrons emitted from the atom in collisions with swift ions exhibit a pronounced interference pattern whose shape can be extremely sensitive to the collision velocity.

DOI: 10.3390/atoms10040125

Related papers

Probing atomic 'quantum grating' by collisions with charged projectiles

S. F. Zhang, Bennaceur Najjari, Xuanye Ma +1 more

The wave function of an atom passed through a diffraction grating acquires a regular space structure and the interaction of another particle with this atom can be thought of as scattering on a 'quantum grating' composed of a single atom. Probing this 'grating' by collisions with charged projectiles reveals interference effects due to coherent contributions of its 'slits' to the transition amplitude. In particular, the spectra of electrons emitted from the atom in collisions with swift ions exhibit a pronounced interference pattern whose shape can be extremely sensitive to the collision velocity.

arXiv:2002.09329Feb 21, 20200 citations

Photoionization of a quantum grating formed by a single atom

S F Zhang, Bennaceur Najjari, X. Ma

Abstract When an atom passes through a macroscopic diffraction grating its wave function acquires a regular space structure and its collision by another particle can be thought of as scattering, of the latter, on a grating composed of a single atom (hereafter termed as ‘quantum-grating’). Photoionization of such a ‘quantum grating’ unveils interference features and in particular a striking difference in the photoelectron and recoil ion spectra which no longer ‘mirroring’ each other as in the case of photoionization of atoms or molecules. We show that complete information about the macroscopic diffraction grating is directly contained in the recoil ion spectra while only partly exhibited in the spectra of the electron.

Journal of Physics B Atomic Molecular and Optical PhysicsAug 4, 20212 citations

Interference and diffraction

P A Davidson

Abstract In Chapter 21, we turn to interference and diffraction. We start by describing the interference pattern in Young’s classic two-slit experiment, whose analysis is subsequently generalised to determine the interference pattern behind a multi-slit grating. The diffraction pattern for a single slit is then estimated using Huygens’ principle, and this is combined with the interference pattern for a multi-slit grating to get the entire wave pattern generated by a diffraction grating. Next, we turn to the diffraction of electrons. This starts with a brief introduction to quantum mechanics, focussed on Schrodinger’s wave equation, de Broglie waves, and the collapse of the wavefunction following measurements. Finally, we use these elementary quantum concepts to describe the diffraction of electrons.

Dec 23, 20250 citations

Interference Phenomena: Exploring the Essential Mystery

Frank S. Levin

Abstract Chapter 11 introduces the essential mystery of quantum mechanics, shows how it is resolved, and then goes on to examine related phenomena. The mystery is how individual photons, not electromagnetic waves, can give rise to the interference pattern seen in the two-slit experiment. They are shown to do so because the relevant quantum amplitude is a linear combination of two terms, leading to the pattern when neither slit is identified as the one the photon went through, but collapsing to one term and no pattern if the slit is identified. Similar results are shown to occur when individual electrons are incident on the two slits, and when large molecules, which have de Broglie wavelengths, are scattered by diffraction gratings. Many other interference experiments are described, including those where a photon was shown to be in two places simultaneously and one where a photon displayed both wave and particle features.

Sep 21, 20170 citations

Matter-wave/atom interferometry

John F. Clauser, Shifang Li

Although interferometry's earliest and most familiar use is with photons, the discovery of matter-wave (deBroglie-wave) interference for electrons demanded the development of quantum mechanics. Since then, matter-wave interferometry has been performed with neutrons, Cooper electron-pairs, and most recently, with whole atoms and diatomic molecules. This talk describes our recent high-flux atom interferometry experiments using the generalized Talbot-vonLau effect. Our interferometer consists of a sequence of three planar vacuum-slit diffraction gratings, microfabricated from silicon nitride membranes. DeBroglie-wave interference fringes are sensed by measuring the transmission of potassium atoms on a hot- wire as a function of grating relative position. Different spatial Fourier components (up to sixth) in the diffraction pattern are resonant in the interferometer at different atomic velocities (i.e., at different wavelengths). When a laser cooled slow atomic beam is incident, various different diffraction patterns are observed as a function of atomic velocity. In an alternative `Heisenberg Microscope' configuration an incident thermal beam produces a velocity average over different fringe Fourier components. AC modulated weak laser light passing through the interferometer interacts selectively with atoms at a specific velocity. The associated fringe pattern is then ac modulated and revealed by its selective destruction.

Proceedings of SPIE, the International Society for Optical Engineering/Proceedings of SPIEDec 12, 19940 citations

Experiments performed in order to reveal fundamental differences between the diffraction and interference of waves and electrons

V.V. Demjanov

Diffraction patterns of electrons are believed to resemble those of electromagnetic waves (EMW). I performed a series of experiments invoked to show that the periodicity of peaks in the diffraction diagram of electrons is concerned with the periodicity of the arrangement of scattering centers in the diffraction grating in combination with the supposed character of the spatial structure of the electron as a system of regularly spaced concentric shells of elasticity. I started from the experiment on the diffraction of electrons and EMWs at the sharp edge of the opaque half-plane. This simple scattering configuration enabled me to discriminate between the re-radiation mechanism of the wave diffraction and ricochet scattering of electrons on the edge of the half-plane. Then I made experiments with scattering on composite objects proceeding step by step from a single straight edge to a couple of edges (one slit) and then to four edges (two slits). Thus I succeeded in interpretation of the double-slit diffraction (four straight edges) in terms of the scattering on a single edge. I managed also to observe the electron's trajectory. Equipping the slit's edge with a semiconductor sensors I registered the passing of the electron through the slit detecting simultaneously a weaker signal at another slit. This technique appeared not to destroy or disturb the "interference" pattern. Closing one slit by inserting therein a transparent for EMWs piece of dielectric I have found that the scattering pattern beneath this slit vanishes while the scattering pattern under the open slit remains as before when both slits were open. This experiment indicates that the electron "interferes" with its electromagnetic component passed via the slit plugged by the transparent for it dielectric.

arXiv:1002.3880Feb 20, 20102 citations