Two-electron quantum walks can probe entanglement and decoherence in an electron microscope

Fuente: arXiv
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Main Authors: Tziperman, Offek, Nabben, David, Ruimy, Ron, Holder, Jacob, Nussinson, Ethan, Fang, Yiqi, Gorlach, Alexey, Kazenwadel, Daniel, Karnieli, Aviv, Kaminer, Ido, Baum, Peter
Format: Preprint
Published: 2025
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author Tziperman, Offek
Nabben, David
Ruimy, Ron
Holder, Jacob
Nussinson, Ethan
Fang, Yiqi
Gorlach, Alexey
Kazenwadel, Daniel
Karnieli, Aviv
Kaminer, Ido
Baum, Peter
author_facet Tziperman, Offek
Nabben, David
Ruimy, Ron
Holder, Jacob
Nussinson, Ethan
Fang, Yiqi
Gorlach, Alexey
Kazenwadel, Daniel
Karnieli, Aviv
Kaminer, Ido
Baum, Peter
contents Classical physics is often a good approximation for quantum systems composed of many interacting particles, although wavepacket dispersion and scattering processes continuously induce delocalization and entanglement. According to decoherence theory, an entangled ensemble can appear classical when only a subset of all particles is observed. This emergence of macroscopic phenomena from quantum interactions is, for example, relevant for phase transitions, quantum thermalization, hydrodynamics, spin liquids, or time crystals. However, entanglement and decoherence in free electrons have not yet been explored, although the electron is a fundamental elementary particle with extraordinary technological relevance. Here, we investigate the degree of coherence and entanglement in a free-space electron gas in the beam of an ultrafast electron microscope. We introduce a two-electron quantum walk that transforms the quantum state into different bases for quantum state tomography of entangled or partially entangled electron-electron pairs. We apply this novel diagnostic to study quantum effects in short pulses of hundreds of electrons under strong Coulomb correlation. We observe a high contrast interference in the electron-electron correlations but no significant signs of electron-electron entanglement which we explain by limited purity of the initial states and decoherence effects from unmeasured reservoir electrons. The ability to characterize quantum states of multiple free electrons may allow verification of electron-electron entanglement for use in fundamental studies and quantum electron microscopy.
format Preprint
id arxiv_https___arxiv_org_abs_2505_03707
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Two-electron quantum walks can probe entanglement and decoherence in an electron microscope
Tziperman, Offek
Nabben, David
Ruimy, Ron
Holder, Jacob
Nussinson, Ethan
Fang, Yiqi
Gorlach, Alexey
Kazenwadel, Daniel
Karnieli, Aviv
Kaminer, Ido
Baum, Peter
Quantum Physics
Classical physics is often a good approximation for quantum systems composed of many interacting particles, although wavepacket dispersion and scattering processes continuously induce delocalization and entanglement. According to decoherence theory, an entangled ensemble can appear classical when only a subset of all particles is observed. This emergence of macroscopic phenomena from quantum interactions is, for example, relevant for phase transitions, quantum thermalization, hydrodynamics, spin liquids, or time crystals. However, entanglement and decoherence in free electrons have not yet been explored, although the electron is a fundamental elementary particle with extraordinary technological relevance. Here, we investigate the degree of coherence and entanglement in a free-space electron gas in the beam of an ultrafast electron microscope. We introduce a two-electron quantum walk that transforms the quantum state into different bases for quantum state tomography of entangled or partially entangled electron-electron pairs. We apply this novel diagnostic to study quantum effects in short pulses of hundreds of electrons under strong Coulomb correlation. We observe a high contrast interference in the electron-electron correlations but no significant signs of electron-electron entanglement which we explain by limited purity of the initial states and decoherence effects from unmeasured reservoir electrons. The ability to characterize quantum states of multiple free electrons may allow verification of electron-electron entanglement for use in fundamental studies and quantum electron microscopy.
title Two-electron quantum walks can probe entanglement and decoherence in an electron microscope
topic Quantum Physics
url https://arxiv.org/abs/2505.03707