Abstract

A method for characterising the wave-function of freely-propagating particles would provide a useful tool for developing quantum-information technologies with single electronic excitations. Previous continuous-variable quantum tomography techniques developed to analyse electronic excitations in the energy-time domain have been limited to energies close to the Fermi level. We show that a wide-band tomography of single-particle distributions is possible using energy-time filtering and that the Wigner representation of the mixed-state density matrix can be reconstructed for solitary electrons emitted by an on-demand single-electron source. These are highly localised distributions, isolated from the Fermi sea. While we cannot resolve the pure state Wigner function of our excitations due to classical fluctuations, we can partially resolve the chirp and squeezing of the Wigner function imposed by emission conditions and quantify the quantumness of the source. This tomography scheme, when implemented with sufficient experimental resolution, will enable quantum-limited measurements, providing information on electron coherence and entanglement at the individual particle level.

Details

Title
Continuous-variable tomography of solitary electrons
Author
Fletcher, J D 1   VIAFID ORCID Logo  ; Johnson, N 2   VIAFID ORCID Logo  ; Locane, E 3 ; See, P 1 ; Griffiths, J P 4 ; Farrer, I 5   VIAFID ORCID Logo  ; Ritchie, D A 4   VIAFID ORCID Logo  ; Brouwer, P W 3 ; Kashcheyevs, V 6   VIAFID ORCID Logo  ; Kataoka, M 1   VIAFID ORCID Logo 

1  National Physical Laboratory, Middlesex, UK 
2  National Physical Laboratory, Middlesex, UK; London Centre for Nanotechnology and Department of Electronic and Electrical Engineering, University College London, London, UK; NTT Basic Research Laboratories, NTT Corporation, Atsugi, Japan 
3  Dahlem Center for Complex Quantum Systems and Institut für Theoretische Physik, Freie Universität Berlin, Berlin, Germany 
4  Cavendish Laboratory, University of Cambridge, Cambridge, UK 
5  Cavendish Laboratory, University of Cambridge, Cambridge, UK; Department of Electronic & Electrical Engineering, The University of Sheffield, Sheffield, UK 
6  Department of Physics, University of Latvia, Riga, Latvia 
Pages
1-7
Publication year
2019
Publication date
Nov 2019
Publisher
Nature Publishing Group
e-ISSN
20411723
Source type
Scholarly Journal
Language of publication
English
DOI
https://doi.org/10.1038/s41467-019-13222-1
ProQuest document ID
2317037114
Copyright
© 2019. This work is published under http://creativecommons.org/licenses/by/4.0/ (the “License”). Notwithstanding the ProQuest Terms and Conditions, you may use this content in accordance with the terms of the License.