Freiburg 2024 – scientific programme
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Q: Fachverband Quantenoptik und Photonik
Q 44: Quantum Information II
Q 44.6: Talk
Thursday, March 14, 2024, 12:15–12:30, HS 1199
Determination of free-electron density matrices using heterodyne detection and maximum likelihood estimation — •Hao Jeng1,2, Jan-Wilke Henke1,2, and Claus Ropers1,2 — 1Max Planck Institute for Multidisciplinary Sciences, D-37077 Göttingen, Germany — 2University of Göttingen, D-37077 Göttingen, Germany
Free electrons interacting with light are known to scatter into superpositions of momentum states [1], but existing methods to determine these density matrices are limited in accuracy [2]. We have developed a reconstruction algorithm based on maximum likelihood estimation that circumvents these issues, and we have used this method to verify the formation of attosecond electron pulses. We have also developed an analogue of optical heterodyne detection for free electrons, which we use to examine the quantum states produced from interactions with light in a waveguide. These techniques greatly simplify the measurement and reconstruction of free-electron states, opening up new routes of investigation into the quantum interaction between free electrons and light.
[1] Feist et al., Nature 521, 200 (2015).
[2] Priebe et al., Nature Photonics 11, 793 (2017).
Keywords: swift electrons; light-matter interaction; quantum tomography; heterodyne detection; maximum likelihood estimation