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A multidimensional approach to quantum state tomography of photoelectron wavepackets

Laurell, H. LU ; Baños-Gutiérrez, J. ; L’Huillier, A. LU orcid ; Busto, D. LU orcid and Finkelstein-Shapiro, D. LU (2025) In Scientific Reports 15(1).
Abstract

There is a growing interest in reconstructing the density matrix of photoelectron wavepackets, in particular in complex systems where decoherence can be introduced either by a partial measurement of the system or through coupling with a stochastic environment. To this end, several methods to reconstruct the density matrix, quantum state tomography protocols, have been developed and tested on photoelectrons ejected from noble gases following absorption of extreme ultraviolet (XUV) photons from attosecond pulses. It remains a challenge to obtain model-free, single scan protocols that can reconstruct the density matrix with high fidelities. Current methods require extensive measurements or involve complex fitting of the signal. Efficient... (More)

There is a growing interest in reconstructing the density matrix of photoelectron wavepackets, in particular in complex systems where decoherence can be introduced either by a partial measurement of the system or through coupling with a stochastic environment. To this end, several methods to reconstruct the density matrix, quantum state tomography protocols, have been developed and tested on photoelectrons ejected from noble gases following absorption of extreme ultraviolet (XUV) photons from attosecond pulses. It remains a challenge to obtain model-free, single scan protocols that can reconstruct the density matrix with high fidelities. Current methods require extensive measurements or involve complex fitting of the signal. Efficient single-scan reconstructions would be of great help to increase the number of systems that can be studied. We propose a new and more efficient protocol that is able to reconstruct the continuous variable density matrix of a photoelectron in a single time delay scan. It is based on measuring the coherences of a photoelectron created by absorption of an XUV pulse using a broadband infrared (IR) probe that is scanned in time and a narrowband IR reference that is temporally fixed to the XUV pulse. We illustrate its performance for a Fano resonance in He as well as mixed states in Ar arising from spin-orbit splitting. We show that the protocol results in excellent fidelities and near-perfect estimation of the purity.

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author
; ; ; and
organization
publishing date
type
Contribution to journal
publication status
published
subject
in
Scientific Reports
volume
15
issue
1
article number
3937
publisher
Nature Publishing Group
external identifiers
  • pmid:39890824
  • scopus:85217731571
ISSN
2045-2322
DOI
10.1038/s41598-025-86701-9
language
English
LU publication?
yes
additional info
Publisher Copyright: © The Author(s) 2025.
id
9d02810d-67bc-402e-af1d-e2ea445ee33f
date added to LUP
2025-03-06 15:46:07
date last changed
2025-07-11 02:39:19
@article{9d02810d-67bc-402e-af1d-e2ea445ee33f,
  abstract     = {{<p>There is a growing interest in reconstructing the density matrix of photoelectron wavepackets, in particular in complex systems where decoherence can be introduced either by a partial measurement of the system or through coupling with a stochastic environment. To this end, several methods to reconstruct the density matrix, quantum state tomography protocols, have been developed and tested on photoelectrons ejected from noble gases following absorption of extreme ultraviolet (XUV) photons from attosecond pulses. It remains a challenge to obtain model-free, single scan protocols that can reconstruct the density matrix with high fidelities. Current methods require extensive measurements or involve complex fitting of the signal. Efficient single-scan reconstructions would be of great help to increase the number of systems that can be studied. We propose a new and more efficient protocol that is able to reconstruct the continuous variable density matrix of a photoelectron in a single time delay scan. It is based on measuring the coherences of a photoelectron created by absorption of an XUV pulse using a broadband infrared (IR) probe that is scanned in time and a narrowband IR reference that is temporally fixed to the XUV pulse. We illustrate its performance for a Fano resonance in He as well as mixed states in Ar arising from spin-orbit splitting. We show that the protocol results in excellent fidelities and near-perfect estimation of the purity.</p>}},
  author       = {{Laurell, H. and Baños-Gutiérrez, J. and L’Huillier, A. and Busto, D. and Finkelstein-Shapiro, D.}},
  issn         = {{2045-2322}},
  language     = {{eng}},
  number       = {{1}},
  publisher    = {{Nature Publishing Group}},
  series       = {{Scientific Reports}},
  title        = {{A multidimensional approach to quantum state tomography of photoelectron wavepackets}},
  url          = {{http://dx.doi.org/10.1038/s41598-025-86701-9}},
  doi          = {{10.1038/s41598-025-86701-9}},
  volume       = {{15}},
  year         = {{2025}},
}