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Measuring the quantum state of photoelectrons

Laurell, Hugo LU ; Luo, Sizuo LU ; Weissenbilder, Robin LU ; Ammitzböll, Mattias LU orcid ; Ahmed, Shahnawaz ; Söderberg, Hugo LU ; Petersson, C. Leon M. ; Poulain, Vénus LU orcid ; Guo, Chen LU and Dittel, Christoph LU , et al. (2025) In Nature Photonics
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... (More)

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.

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organization
publishing date
type
Contribution to journal
publication status
epub
subject
in
Nature Photonics
article number
5042
publisher
Nature Publishing Group
external identifiers
  • scopus:85217249949
ISSN
1749-4885
DOI
10.1038/s41566-024-01607-8
language
English
LU publication?
yes
additional info
Publisher Copyright: © The Author(s) 2025.
id
f9d67b84-3c91-4228-a6cc-1b77c1ae287b
date added to LUP
2025-03-06 15:43:53
date last changed
2025-04-04 15:40:53
@article{f9d67b84-3c91-4228-a6cc-1b77c1ae287b,
  abstract     = {{<p>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.</p>}},
  author       = {{Laurell, Hugo and Luo, Sizuo and Weissenbilder, Robin and Ammitzböll, Mattias and Ahmed, Shahnawaz and Söderberg, Hugo and Petersson, C. Leon M. and Poulain, Vénus and Guo, Chen and Dittel, Christoph and Finkelstein-Shapiro, Daniel and Squibb, Richard J. and Feifel, Raimund and Gisselbrecht, Mathieu and Arnold, Cord L. and Buchleitner, Andreas and Lindroth, Eva and Frisk Kockum, Anton and L’Huillier, Anne and Busto, David}},
  issn         = {{1749-4885}},
  language     = {{eng}},
  publisher    = {{Nature Publishing Group}},
  series       = {{Nature Photonics}},
  title        = {{Measuring the quantum state of photoelectrons}},
  url          = {{http://dx.doi.org/10.1038/s41566-024-01607-8}},
  doi          = {{10.1038/s41566-024-01607-8}},
  year         = {{2025}},
}