학술논문
Measuring the quantum state of photoelectrons
Document Type
Working Paper
Author
Laurell, Hugo; Luo, Sizuo; Weissenbilder, Robin; Ammitzböll, Mattias; Ahmed, Shahnawaz; Söderberg, Hugo; Petersson, C. Leon M.; Poulain, Vénus; Guo, Chen; Dittel, Christoph; Finkelstein-Shapiro, Daniel; Squibb, Richard J.; Feifel, Raimund; Gisselbrecht, Mathieu; Arnold, Cord L.; Buchleitner, Andreas; Lindroth, Eva; Kockum, Anton Frisk; L'Huillier, Anne; Busto, David
Source
Subject
Language
Abstract
A photoelectron, emitted due to the absorption of light quanta as described by the photoelectric effect, is often characterized experimentally by a classical quantity, its momentum. However, since the photoelectron is a quantum object, its rigorous characterization requires the reconstruction of the complete quantum state, the photoelectron's density matrix. Here, we use quantum state tomography to fully characterize photoelectrons emitted from helium and argon atoms upon absorption of ultrashort, extreme ultraviolet light pulses. While in helium we measure a pure photoelectronic state, in argon, spin-orbit interaction induces entanglement between the ion and the photoelectron, leading to a reduced purity of the photoelectron state. Our work shows how state tomography gives new insights into the fundamental quantum aspects of light-induced electronic processes in matter, bridging the fields of photoelectron spectroscopy and quantum information, and offering new spectroscopic possibilities for quantum technology.