Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Log inSign up
Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Blog
Job Board
Q3AS

© 2026 Aqora Quantum S.A.S.

TermsPrivacyLegal Notice

arXiv:2011.09649 · Physical Review A

Quantum control of entangled photon-pair generation in electron-atom collisions driven by laser-synthesized free-electron wave packets

R. Esteban Goetz, Klaus Bartschat

Published Apr 16, 2021• 3 citations
arXivHTMLPDF

Abstract

We propose an extension of coherent control using laser-synthesized free-electron matter waves. In contrast to coherent control schemes exploiting optical coherences to steer the dynamics of matter waves, we analyze the opposite and investigate the control of quantum light emission driven by laser-sculpted coherent free-electron matter waves. We apply this concept to the control of entangled photon-pair emission in electron-atom collisions, in which the incident electron wave packet, colliding with a target atom $B$, is engineered by interferometric resonantly enhanced multiphoton ionization of a parent atom $A$. Each ionization pathway leads to electron wave packets that coherently interfere during temporal evolution in the continuum. Their mutual coherence can be controlled by adjusting the relative phases or time delays of the frequency components of the ionizing field contributing to the interfering pathways. We report coherent control of entangled photon-pair generation in radiative photocascade emission upon decay of the target atom after inelastic excitation triggered by the collision with the synthesized electron wave packet.

DOI
10.1103/physreva.103.043112

Related papers

Quantum control of entangled photon-pair generation in electron-atom collisions driven by multiphoton-tailored free-electron wave packets

R. Esteban Goetz, Klaus Bartschat

Two-pathway coherent control of photoionization is an example of control of matter waves using light. Here, we analyze the opposite and investigate the control of quantum light using matter waves. We report coherent control of entangled photon-pair emission in electron-atom collisions mediated by transfer of the temporal and atomic coherence carried by the incident electron wave packet. The latter is engineered by resonantly-enhanced multiphoton ionization exploiting interfering ionization pathways. We show that both sources of coherence can be used to control the angular distributions of photons emitted by radiative cascade upon optical decay in the target atom, offering the possibility of coherent control driven by sculpted matter waves via transfer of optical and atomic coherence.

•Nov 19, 2020•0 citations

Coherent Control of Absorption and Entanglement via Ultrafast Strong Coupling

Axel Stenquist

This thesis investigates quantum dynamics induced in atoms by ultrashort pulses of light. The work is motivated by recent developments in free-electron lasers, which generate ultrashort pulses of intense, coherent light and enable coherent control of quantum dynamics. We develop theoretical models to study the processes of absorption and emission in laser-atom interactions. Additionally, we study photoionisation, which creates an ion and an electron, and the entanglement that can be generated between these particles. Finally, we have investigated how the spontaneous decay of the ion induces entanglement transfer from the ion-electron pair to the electron-photon pair.This thesis compiles seven papers. Paper I investigates the absorption of light from an attosecond pulse by an atom in a prepared coherent superposition of states. We show how the evolution of the phase of the superposition wave packet influences the attosecond transient absorption spectra. Paper II predicts the existence of Mollow-like triplets in the absorption spectra of strongly coupled atoms. We establish the conditions for the pulse envelope under which this triplet pattern can be supported.Paper III studies two-photon Rabi oscillations, establishing which systems can sustain such dynamics. We find that a two-photon Rabi oscillating system can induce giant counter-rotating oscillations in the population dynamics, enabling investigations of physical effects beyond the rotating-wave approximation.Paper IV studies ionisation from an atom strongly coupled by a dichromatic field, where interference between the two frequency components shapes the temporal symmetry of the atomic dynamics, allowing for coherent control of the photoelectron distribution.Paper V considers an experiment performed at a Free-Electron Laser facility where a helium atom is ionised and the resulting ion is subsequently strongly coupled. The photoelectron spectra are theoretically reproduced and the entanglement between the ion and photoelectron is studied. Paper VI investigates how the entanglement in the ion--electron pair, generated via photoionisation followed by strong coupling, can be coherently controlled by harnessing the time symmetry of the pulse. We find that the observable manifestation of the entanglement can be altered in such a way that the electron energy becomes associated with the ionic state, allowing the entanglement to be detected via coincidence measurements. Paper VII investigates how quantum correlations between the ion and the electron can be coherently controlled by sequential strong coupling of the ion. We find that both the build-up of entanglement and its manifestation can be controlled, and we establish a quantitative measure of the amplitude entanglement that explains the dynamics in an intuitive way. Paper VIII studies the process of entanglement transfer induced by the spontaneous decay of the ion. We find that the ion--electron entanglement generated during the ultrashort interaction with the laser field is transferred to the electron--photon system over the much longer timescale of fluorescence.

•Sep 3, 2026•0 citations

Coherent control of electron-ion entanglement in multiphoton ionization

Yi-Jia Mao, Zhaohan Zhang, Yang Li +3 more

Quantitative control and measurement of quantum entanglement are essential for advancing quantum technologies. Photoionization induced by ultrashort laser pulses provides a unique platform for studying entanglement between photoelectrons and residual ions, representing one of the most intriguing quantum phenomena in attosecond physics. Although extensive studies have focused on the coherence properties within either the emitted electrons or the ions individually, the electron-ion entanglement has remained largely unexplored. In this work, we bridge this gap by investigating the resonance-enhanced multiphoton ionization of argon atoms driven by two time-delayed ultrashort ultraviolet pulses. Employing state-of-the-art first-principles multi-electron simulations, we demonstrate the ability to reconstruct and precisely manipulate the purity of electron quantum states through detailed analysis of the photoelectron angular distributions. Our results reveal distinct scattering-phase differences among various electron configurations within the same partial wave channel, providing unequivocal evidence of electron-ion correlation and entanglement. With the fast development of free-electron lasers, this study establishes an experimentally feasible framework for directly controlling quantum entanglement in ultrafast ionization processes, offering new insights and powerful methodologies for exploring complex electron dynamics in many-electron systems.

Light Science & Applications•Mar 6, 2026•1 citation

Coherent control of third-harmonic generation and multiphoton ionization: Experimental and theoretical studies

Roberto Buffa, R. Eramo, CAVALIERI, STEFANO +1 more

The effect of temporal coherent control on the two-photon-resonant third-harmonic generation and multiphoton ionization into the continuum states of an atomic system is experimentally and theoretically investigated by means of a pair of partially incoherent, identical laser pulses. The evidence of quantum interference as a function of the delay between the pulses is reported. The transition from the resonant to the nonresonant case is also shown. The obtained results agree with the prediction of a theoretical model showing that the onset of quantum interference appears to be related to the coherence time of the laser radiation, which is much shorter than the pulse duration.

•Jan 1, 2005•0 citations

Coherent control of atoms in the extreme ultraviolet and attosecond regime by synchrotron radiation

T. Kaneyasu, Y. Hikosaka, Masaki Fujimoto +2 more

Abstract Control of interference between wave packets is one of the basic concepts in coherent control that enables quantum manipulation of populations and reaction pathways in matter. We have recently shown a new method to achieve coherent control in the extreme ultraviolet and attosecond regime using synchrotron radiation. This method is based on the use of longitudinal coherence of light wave packets that are naturally included in the undulator radiation. For quantum manipulation of atomic systems, wave packet interference is precisely controlled by tuning the time delay between the light wave packets. Here we show that the quantum phase controlled by the time delay can be monitored as an initial phase of the quantum beat oscillation in fluorescence decay.

Journal of Physics Conference Series•Dec 1, 2022•0 citations

Generation of entangled lights with temporally reversed photon wave packets

Sergey A. Moiseev, Byoung Seung HAM

We theoretically study the control of a weak quantum light in a resonant three-level condensed medium derived by a pair of resonant counterpropagating laser fields. We analytically demonstrate that the adiabatic switching on of one of the control fields generates an entangled state of photon wave packets moving together at subnormal slow velocity in the medium with relative amplitudes determined by the control laser fields. An abrupt switching-off the control field makes the entangled wave packets propagate in the opposite direction with temporally reversed profiles relative to each other. We have analyzed the quantum control of the entanglement generation in terms of the adiabatic and nonadiabatic switching operations of the coupling laser pulse.

Physical Review A•May 3, 2005•26 citations
We propose an extension of coherent control using laser-synthesized free-electron matter waves. In contrast to coherent control schemes exploiting optical coherences to steer the dynamics of matter waves, we analyze the opposite and investigate the control of quantum light emission driven by laser-sculpted coherent free-electron matter waves. We apply this concept to the control of entangled photon-pair emission in electron-atom collisions, in which the incident electron wave packet, colliding with a target atom BBB, is engineered by interferometric resonantly enhanced multiphoton ionization of a parent atom AAA. Each ionization pathway leads to electron wave packets that coherently interfere during temporal evolution in the continuum. Their mutual coherence can be controlled by adjusting the relative phases or time delays of the frequency components of the ionizing field contributing to the interfering pathways. We report coherent control of entangled photon-pair generation in radiative photocascade emission upon decay of the target atom after inelastic excitation triggered by the collision with the synthesized electron wave packet.
Two-pathway coherent control of photoionization is an example of control of matter waves using light. Here, we analyze the opposite and investigate the control of quantum light using matter waves. We report coherent control of entangled photon-pair emission in electron-atom collisions mediated by transfer of the temporal and atomic coherence carried by the incident electron wave packet. The latter is engineered by resonantly-enhanced multiphoton ionization exploiting interfering ionization pathways. We show that both sources of coherence can be used to control the angular distributions of photons emitted by radiative cascade upon optical decay in the target atom, offering the possibility of coherent control driven by sculpted matter waves via transfer of optical and atomic coherence.
This thesis investigates quantum dynamics induced in atoms by ultrashort pulses of light. The work is motivated by recent developments in free-electron lasers, which generate ultrashort pulses of intense, coherent light and enable coherent control of quantum dynamics. We develop theoretical models to study the processes of absorption and emission in laser-atom interactions. Additionally, we study photoionisation, which creates an ion and an electron, and the entanglement that can be generated between these particles. Finally, we have investigated how the spontaneous decay of the ion induces entanglement transfer from the ion-electron pair to the electron-photon pair.This thesis compiles seven papers. Paper I investigates the absorption of light from an attosecond pulse by an atom in a prepared coherent superposition of states. We show how the evolution of the phase of the superposition wave packet influences the attosecond transient absorption spectra. Paper II predicts the existence of Mollow-like triplets in the absorption spectra of strongly coupled atoms. We establish the conditions for the pulse envelope under which this triplet pattern can be supported.Paper III studies two-photon Rabi oscillations, establishing which systems can sustain such dynamics. We find that a two-photon Rabi oscillating system can induce giant counter-rotating oscillations in the population dynamics, enabling investigations of physical effects beyond the rotating-wave approximation.Paper IV studies ionisation from an atom strongly coupled by a dichromatic field, where interference between the two frequency components shapes the temporal symmetry of the atomic dynamics, allowing for coherent control of the photoelectron distribution.Paper V considers an experiment performed at a Free-Electron Laser facility where a helium atom is ionised and the resulting ion is subsequently strongly coupled. The photoelectron spectra are theoretically reproduced and the entanglement between the ion and photoelectron is studied. Paper VI investigates how the entanglement in the ion--electron pair, generated via photoionisation followed by strong coupling, can be coherently controlled by harnessing the time symmetry of the pulse. We find that the observable manifestation of the entanglement can be altered in such a way that the electron energy becomes associated with the ionic state, allowing the entanglement to be detected via coincidence measurements. Paper VII investigates how quantum correlations between the ion and the electron can be coherently controlled by sequential strong coupling of the ion. We find that both the build-up of entanglement and its manifestation can be controlled, and we establish a quantitative measure of the amplitude entanglement that explains the dynamics in an intuitive way. Paper VIII studies the process of entanglement transfer induced by the spontaneous decay of the ion. We find that the ion--electron entanglement generated during the ultrashort interaction with the laser field is transferred to the electron--photon system over the much longer timescale of fluorescence.
Quantitative control and measurement of quantum entanglement are essential for advancing quantum technologies. Photoionization induced by ultrashort laser pulses provides a unique platform for studying entanglement between photoelectrons and residual ions, representing one of the most intriguing quantum phenomena in attosecond physics. Although extensive studies have focused on the coherence properties within either the emitted electrons or the ions individually, the electron-ion entanglement has remained largely unexplored. In this work, we bridge this gap by investigating the resonance-enhanced multiphoton ionization of argon atoms driven by two time-delayed ultrashort ultraviolet pulses. Employing state-of-the-art first-principles multi-electron simulations, we demonstrate the ability to reconstruct and precisely manipulate the purity of electron quantum states through detailed analysis of the photoelectron angular distributions. Our results reveal distinct scattering-phase differences among various electron configurations within the same partial wave channel, providing unequivocal evidence of electron-ion correlation and entanglement. With the fast development of free-electron lasers, this study establishes an experimentally feasible framework for directly controlling quantum entanglement in ultrafast ionization processes, offering new insights and powerful methodologies for exploring complex electron dynamics in many-electron systems.
The effect of temporal coherent control on the two-photon-resonant third-harmonic generation and multiphoton ionization into the continuum states of an atomic system is experimentally and theoretically investigated by means of a pair of partially incoherent, identical laser pulses. The evidence of quantum interference as a function of the delay between the pulses is reported. The transition from the resonant to the nonresonant case is also shown. The obtained results agree with the prediction of a theoretical model showing that the onset of quantum interference appears to be related to the coherence time of the laser radiation, which is much shorter than the pulse duration.
Abstract Control of interference between wave packets is one of the basic concepts in coherent control that enables quantum manipulation of populations and reaction pathways in matter. We have recently shown a new method to achieve coherent control in the extreme ultraviolet and attosecond regime using synchrotron radiation. This method is based on the use of longitudinal coherence of light wave packets that are naturally included in the undulator radiation. For quantum manipulation of atomic systems, wave packet interference is precisely controlled by tuning the time delay between the light wave packets. Here we show that the quantum phase controlled by the time delay can be monitored as an initial phase of the quantum beat oscillation in fluorescence decay.
We theoretically study the control of a weak quantum light in a resonant three-level condensed medium derived by a pair of resonant counterpropagating laser fields. We analytically demonstrate that the adiabatic switching on of one of the control fields generates an entangled state of photon wave packets moving together at subnormal slow velocity in the medium with relative amplitudes determined by the control laser fields. An abrupt switching-off the control field makes the entangled wave packets propagate in the opposite direction with temporally reversed profiles relative to each other. We have analyzed the quantum control of the entanglement generation in terms of the adiabatic and nonadiabatic switching operations of the coupling laser pulse.