Wave function of a photoelectron and its collapse in the photoemission process

TL;DR

This paper demonstrates that the wave function of a photoelectron behaves as a wave packet matching the incident light pulse, and provides experimental evidence of wave function collapse through pulse width measurements.

Contribution

It introduces a theoretical model linking the photoelectron wave function to the light pulse and experimentally confirms wave function collapse in photoemission.

Findings

Photoelectron wave function is a wave packet with the same width as the light pulse

Detection pulses are shorter than the light pulse and independent of noise sources

Experimental observation supports the wave function as a probability distribution

Abstract

Based on the first-order perturbation theory, we show that the wave function of a photoelectron is a wave packet with the same width as the incident light pulse. Photoelectron detection measurements revealed that the widths of signal pulses were much shorter than the light pulse and independent of the origin (photoemission or other noises), which is an experimental observation of the wave function collapse. Signal pulses of photoelectrons were distributed along the time axis within the same width as the light pulse, consistent with the interpretation of a wave function as a probability distribution.