“Does the wavepacket dimension of a free-electron quantum wavefunction have physical significance? Can it be measured?” “What is the role of wave-particle duality in quantum interactions between light and matter?” These questions lay in the foundations of Quantum Mechanics since its early inception. 

In this presentation we respond to these challenges by presenting a universal formulation for interactions of single free electrons with light in general interaction schemes, such as Free Electron Lasers (FEL), laser accelerators (DLA), and Photon-induced Near-field Electron Microscopy (PINEM). The formulation is based on modeling the electron as a quantum wavepacket of minimal Heisenberg uncertainty in Energy-Time phase-space [1,2]. The topology of the wavepacket distribution in phase-space at the entrance to the interaction region determines entirely three regimes of interaction with distinct characteristics of post-interaction phase-space (Wigner) distribution and energy spectrum [3]:

-Quantum regime, with PINEM-kind electron energy spectrum of discrete sidebands.

-Point-particle acceleration electron energy spectrum.

-A newly reported intermediate regime of quantum interference - Anomalous PINEM. 

This new formulation resolves the particle-wave duality question, delineates the transition from quantum to classical electrodynamics, and establishes the measurability and reality of the history-dependent quantum electron wavefunction size, shape and envelop modulation. We consequently propose new concepts of electron microscopy based on optical frequency modulation of the electron wavefunction envelope: “Free-Electron Bound-Electron Resonant Interaction (FEBERI)” and “Resonant Cathodoluminescence (RCL)”.

Reference

1.  A. Gover, Y. Pan, "Dimension-Dependent Stimulated Radiative Interaction of a Single Electron Quantum Wavepacket", Phys. Lett. A 382, pp. 1550-1555 (2018).

2.  Pan, Yiming, and Avraham Gover. "Spontaneous and stimulated emissions of a preformed quantum free-electron wave function." Physical Review A 99.5 (2019): 052107.

3. Pan, Yiming, Bin Zhang, and Avraham Gover. "Anomalous Photon-induced Near-field Electron Microscopy." Physical review letters 122.18 (2019): 183204.