Momentum Imaging of Electron Wave Packet Interference

Yu.S. Korobochko, B. D. Grachev, V.I. Mineev

Junheng Pan, Shaoran Liu, Bozhou Zhang +2 more

Abstract In Copenhagen’s interpretation, a self-interference mechanism is assumed for a wave function to split and to pass through the slits simultaneously, then recombine and collapse to generate a dot signal on a detector. Its use of a single wave function to describe a whole ensemble without accounting for a particle’s individuality is incomplete. To better understand the single-electron double-slit interference, we use a wave-packet trajectory approach to track each electron’s dynamics and calculate the time-dependent interference intensity. We analyze the self-interference and cross-interference mechanisms to illustrate how an electron’s coherence length affects the self-interference and how it dictates the wave packet overlaps between adjacent electrons for the cross-interference mechanism to be effective. To circumvent a conflicting dilemma between the electron’s indivisibility and its wave-packet split while passing through the slits, we consider an alternate mechanism involving slit-induced quantized momentum. This mechanism preserves the electron’s indivisibility and avoids the illusive split, recombination and mysterious collapse of a single particle’s wave function.

FRANZ HASSELBACH

R. R. Jones, M. B. Campbell

A technique for determining the quantum state of electronic wave packets from probability distribution measurements is presented. Specifically, a measurement of the fractional probability in each of a wave packet's constituent eigenstates can be used in conjunction with a measurement of the wave packet's time-dependent probability distribution to recover the complex amplitude of each constituent eigenstate. The method is demonstrated for radial Rydberg wave packets using previously measured time-dependent probability distributions in coordinate and momentum space. By exploiting delay imaging techniques, it should be possible to retrieve the quantum state of wave packets in real time.

Luca Pedrelli

Xinhua Xie

We propose a two-dimensional interferometry based on the electron wave-packet interference by using a cycle-shaped orthogonally polarized two-color laser field. With such a method, the subcycle and intercycle interferences can be disentangled into different directions in the measured photoelectron momentum spectra. The Coulomb influence can be minimized and the overlapping of interference fringes with the complicated low-energy structures can be avoided as well. The contributions of the excitation effect and the long-range Coulomb potential can be traced in the Fourier domain of the photoelectron distribution. Because of these advantages, precise information on valence electron dynamics of atoms or molecules with attosecond temporal resolution and additional spatial information with angstrom resolution can be obtained with the two-dimensional electron wave-packet interferometry.