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

Quantum Electronics and Laser Science Conference

Laser-induced antiproton-positron recombination in traps

Maria V. Ryabinina, Leonid A. Melnikov, Vladimir Leonardovich Derbov, Vladislav Viktorovich Serov

Published Jun 25, 2003• 1 citation
Publisher

Abstract

Summary form only given. In the present report we propose a combination of pulsed electric field and laser pulse field at wavelength near 800 nm to stimulate the formation of antihydrogen atoms in lower states (n = 3) in positron-antiproton plasma under the conditions of Penning and Paul traps at low temperatures. The laser intensity estimated is about dozens of W/cm/sup 2/. In crossed constant magnetic field and circularly polarized alternating electric fields a new kind of stationary rotating wave packet states were shown to arise in hydrogen-like systems under special conditions. These packets, knows as Trojan states, remain strongly localized and thus differ significantly from common Rydberg states. Using numerical modeling of wave packet dynamics we analyse the stability of these states with respect to field perturbations and estimate the possibility to use them as intermediate states for antihydrogen production. We discuss the polarization dependencies of the laser-induced recombination rate for the case of the anisotropic velocity distribution.

DOI
10.1109/qels.2002.1031086

Related papers

Laser-induced radiative recombination of antihydrogen in a magnetic field through a quasi-stationary state

Vladislav Viktorovich Serov, Vladimir Leonardovich Derbov, Sergue Il'ich Vinitsky

To increase the efficiency of laser-induced recombination of antihydrogen from cold antihydrogen—positron plasma in a trap, it is proposed to use a new resonance mechanism with the participation of positron quasi-stationary states, arising under the joint action of an antiproton Coulomb field and a strong magnetic field of the trap. The recombination rate is expressed through the atomic laser ionization cross section whose frequency dependence is nonmonotonic due to the presence of quasi-stationary states against the background of the continuum. The estimates with the use of the ionization cross sections calculated earlier demonstrate the possibility of improving the efficiency of the laser-induced recombination at an optimally selected laser frequency.

Optics and Spectroscopy•Apr 1, 2007•7 citations

Laser-stimulated radiative recombination of antihydrogen in a magnetic field in the presence of Doppler broadening

Vladislav Viktorovich Serov, Vladimir Leonardovich Derbov, V. I. Lobanov +3 more

To enhance the laser-stimulated recombination of antihydrogen from cold antiproton-positron plasma in a trap we propose to use a new resonance mechanism involving the quasi-stationary states of the positron that arise from the joint action of the Coulomb field of the antiproton and the strong magnetic field of the trap. The recombination rate is expressed via the cross-section of laser ionization of the atom that has strongly non-monotonic frequency dependence due to the presence of quasi-stationary states merged into the continuum background. The estimates using previously calculated ionization cross-section show the possibility to enhance the laser-stimulated recombination by means of the optimal laser frequency choice.

•Jun 13, 2007•0 citations

The Production and Investigation of Cold Antihydrogen Atoms

H. Pittner

This work reports on experiments in which antihydrogen atoms have been produced in cryogenic Penning traps from antiproton and positron plasmas by two different methods and on experiments that have been carried out subsequently in order to investigate the antihydrogen atoms. By the first method antihydrogen atoms have been formed during the process of positron cooling of antiprotons in so called nested Penning traps and detected via a field ionization method. A linear dependence of the number of detected antihydrogen atoms on the number of positrons has been found. A measurement of the state distribution has revealed that the antihydrogen atoms are formed in highly excited states. This suggests along with the high production rate that the antihydrogen atoms are formed by three-body recombination processes and subsequent collisional deexcitations. However current theory cannot yet account for the measured state distribution. Typical radii of the detected antihydrogen atoms lie in the range between 0.4 µm and 0.15 µm. The deepest bound antihydrogen atoms have radii below 0.1 µm. Antihydrogen atoms with that size have chaotic positron orbits so that for the first time antihydrogen atoms have been detected that cannot be described by the GCA-model. The kinetic energy of the weakest bound antihydrogen atoms has been measured to about 200 meV, which corresponds to an antihydrogen velocity of approximately 6200 m/s. A simple model suggests that these atoms are formed from only one deexcitation collision and methods that might lead to a decrease of the antihydrogen velocity are presented. By the second method antihydrogen atoms have been synthesized in charge-exchange processes. Lasers are used to produce a Rydberg cesium beam within the cryogenic Penning trap that collides with trapped positrons so that Rydberg positronium atoms are formed via charge-exchange reactions. Due to their charge neutrality the Rydberg positronium atoms are free to leave the positron trapping region. The Rydberg positronium atoms that collide with nearby stored antiprotons form antihydrogen atoms in charge-exchange reactions. So far, 14 +/- 4 antihydrogen atoms have been detected background-free via a field-ionization method. The antihydrogen atoms produced via the two-step charge-exchange mechanism are expected to have a temperature of 4.2 K, the temperature of the antiprotons from which they are formed. A method is proposed by which the antihydrogen temperature can be determined with an accuracy of better than 1 K from a measurement of the time delay between antihydrogen annihilation events and the laser pulse that initiates the antihydrogen production via the production of Rydberg cesium atoms. First experiments have been carried out during the last days of the 2004 beam time, but the number of detected antihydrogen annihilations has been too low for a determination of the antihydrogen temperature. Trapped antiprotons have been directly exposed to laser light delivered by a Titanium:Sapphire laser in order to investigate if the laser light causes any loss on the trapped antiprotons. Experiments have shown that no extra loss occurs for laser powers of less than 590 mW. This is an important result against the background of the future plan to confine antihydrogen atoms in a combined Penning-Ioffe trap and then to carry out laser spectroscopy on these atoms, since it reveals that laser light does not cause an increase of the pressure in the trapping region to the extend that annihilations with the background gas become noticeable. The ATRAP Collaboration plans to precisely investigate antihydrogen atoms. The ultimate goal is to test the CPT-theorem by a high precision measurement of the 1S-2S transition of antihydrogen and a comparison with the precisely known value of the corresponding transition in hydrogen. This thesis presents the achievement of the first step towards this challenging goal: the production of cold antihydrogen itself.

•Jan 1, 2005•0 citations

Formation of antihydrogen in an antiproton-positron Debye plasma in the presence of an external laser field

Sougata Mukhopadhyay, Chittaranjan Sinha

We study quantum mechanically the influence of an external laser field on the antihydrogen ($\overline{\mathrm{H}}$) formation cross sections in ground and excited states (2$s$,2$p$) via the three-body recombination process inside a dense plasma of antiprotons and positrons, supposed to be the most efficient mechanism for cold and trapped antihydrogen. The plasma screening is considered in the framework of a Debye- H\"uckel potential. The laser polarization is chosen to be parallel to the incident momentum of the passive positron. The modifications due to the presence of the laser field are found to be quite significant both quantitatively and qualitatively for all the states. In the presence of a laser, the $\overline{\mathrm{H}}$ formation cross sections are found to be suppressed significantly with respect to the field-free situation particularly in the ground state, while the excited state cross sections are in general enhanced at very low incident energies but are again suppressed at higher energies except for some special cases. The sensitivity of the formation cross sections with respect to the Debye length are also studied both in the laser-assisted and in the field-free situations. At very low incident energies, the ground state multiphoton formation is found to enhance with the increase in Debye screening, while the reverse is true for the excited states. These findings should have important implications for future $\overline{\mathrm{H}}$ studies.

Physical Review A•Sep 11, 2013•10 citations

Collisions between anti-particles in presence of laser field

Chittaranjan Sinha, S. Ghosh Deb

Three body recombination (TBR) process for the formation of antihydrogen () inside a trapped plasma of antiprotons () and positrons (e+), supposed to be the most efficient mechanism for the production of cold and trapped antihydrogen is studied quantum mechanically. Present study also involves a background laser field anticipating further enhancement of the formation cross sections. Significantly large cross sections are obtained in the presence of the field at lower incident energies as compared to the field free ones. Cross sections are enhanced for higher excited states of ().

Journal of Physics Conference Series•Sep 1, 2009•0 citations

Antihydrogen formation from laser-assisted antiproton-positronium collisions

Kévin Lévêque-Simon, Paul-Antoine Hervieux

The formation of antihydrogen atoms from three-body collisions between positronium atoms and antiprotons plays a crucial role in the gravitational behavior of antihydrogen at rest (GBAR) experiment devoted to the measure of the action of gravity on antimatter. One of the main challenges facing this experiment is to find the means for increasing the production of antihydrogens which are produced by the reaction $\overline{p}+\text{Ps}\ensuremath{\rightarrow}\overline{\text{H}}+{e}^{\ensuremath{-}}$ with an extremely low rate. Along these lines, we investigate here the possibility to influence the collision process by using a laser field. A perturbative approach combining the Coulomb-Born approximation for modeling the charged-particle collision and a first-order perturbation theory for describing laser-atom interactions is employed to estimate laser-mediated charge-exchange cross sections. By carefully considering the laser specifications compatible with the experimental constraints, we present an extensive study of the influence of the laser parameters (laser wavelength and intensity) on the cross sections in the energy range of interest for GBAR. We show that under special irradiation conditions the rate of antihydrogen production may be significantly increased by the presence of the laser field.

Physical Review A•May 30, 2023•6 citations
Summary form only given. In the present report we propose a combination of pulsed electric field and laser pulse field at wavelength near 800 nm to stimulate the formation of antihydrogen atoms in lower states (n = 3) in positron-antiproton plasma under the conditions of Penning and Paul traps at low temperatures. The laser intensity estimated is about dozens of W/cm/sup 2/. In crossed constant magnetic field and circularly polarized alternating electric fields a new kind of stationary rotating wave packet states were shown to arise in hydrogen-like systems under special conditions. These packets, knows as Trojan states, remain strongly localized and thus differ significantly from common Rydberg states. Using numerical modeling of wave packet dynamics we analyse the stability of these states with respect to field perturbations and estimate the possibility to use them as intermediate states for antihydrogen production. We discuss the polarization dependencies of the laser-induced recombination rate for the case of the anisotropic velocity distribution.
To increase the efficiency of laser-induced recombination of antihydrogen from cold antihydrogen—positron plasma in a trap, it is proposed to use a new resonance mechanism with the participation of positron quasi-stationary states, arising under the joint action of an antiproton Coulomb field and a strong magnetic field of the trap. The recombination rate is expressed through the atomic laser ionization cross section whose frequency dependence is nonmonotonic due to the presence of quasi-stationary states against the background of the continuum. The estimates with the use of the ionization cross sections calculated earlier demonstrate the possibility of improving the efficiency of the laser-induced recombination at an optimally selected laser frequency.
To enhance the laser-stimulated recombination of antihydrogen from cold antiproton-positron plasma in a trap we propose to use a new resonance mechanism involving the quasi-stationary states of the positron that arise from the joint action of the Coulomb field of the antiproton and the strong magnetic field of the trap. The recombination rate is expressed via the cross-section of laser ionization of the atom that has strongly non-monotonic frequency dependence due to the presence of quasi-stationary states merged into the continuum background. The estimates using previously calculated ionization cross-section show the possibility to enhance the laser-stimulated recombination by means of the optimal laser frequency choice.
This work reports on experiments in which antihydrogen atoms have been produced in cryogenic Penning traps from antiproton and positron plasmas by two different methods and on experiments that have been carried out subsequently in order to investigate the antihydrogen atoms. By the first method antihydrogen atoms have been formed during the process of positron cooling of antiprotons in so called nested Penning traps and detected via a field ionization method. A linear dependence of the number of detected antihydrogen atoms on the number of positrons has been found. A measurement of the state distribution has revealed that the antihydrogen atoms are formed in highly excited states. This suggests along with the high production rate that the antihydrogen atoms are formed by three-body recombination processes and subsequent collisional deexcitations. However current theory cannot yet account for the measured state distribution. Typical radii of the detected antihydrogen atoms lie in the range between 0.4 µm and 0.15 µm. The deepest bound antihydrogen atoms have radii below 0.1 µm. Antihydrogen atoms with that size have chaotic positron orbits so that for the first time antihydrogen atoms have been detected that cannot be described by the GCA-model. The kinetic energy of the weakest bound antihydrogen atoms has been measured to about 200 meV, which corresponds to an antihydrogen velocity of approximately 6200 m/s. A simple model suggests that these atoms are formed from only one deexcitation collision and methods that might lead to a decrease of the antihydrogen velocity are presented. By the second method antihydrogen atoms have been synthesized in charge-exchange processes. Lasers are used to produce a Rydberg cesium beam within the cryogenic Penning trap that collides with trapped positrons so that Rydberg positronium atoms are formed via charge-exchange reactions. Due to their charge neutrality the Rydberg positronium atoms are free to leave the positron trapping region. The Rydberg positronium atoms that collide with nearby stored antiprotons form antihydrogen atoms in charge-exchange reactions. So far, 14 +/- 4 antihydrogen atoms have been detected background-free via a field-ionization method. The antihydrogen atoms produced via the two-step charge-exchange mechanism are expected to have a temperature of 4.2 K, the temperature of the antiprotons from which they are formed. A method is proposed by which the antihydrogen temperature can be determined with an accuracy of better than 1 K from a measurement of the time delay between antihydrogen annihilation events and the laser pulse that initiates the antihydrogen production via the production of Rydberg cesium atoms. First experiments have been carried out during the last days of the 2004 beam time, but the number of detected antihydrogen annihilations has been too low for a determination of the antihydrogen temperature. Trapped antiprotons have been directly exposed to laser light delivered by a Titanium:Sapphire laser in order to investigate if the laser light causes any loss on the trapped antiprotons. Experiments have shown that no extra loss occurs for laser powers of less than 590 mW. This is an important result against the background of the future plan to confine antihydrogen atoms in a combined Penning-Ioffe trap and then to carry out laser spectroscopy on these atoms, since it reveals that laser light does not cause an increase of the pressure in the trapping region to the extend that annihilations with the background gas become noticeable. The ATRAP Collaboration plans to precisely investigate antihydrogen atoms. The ultimate goal is to test the CPT-theorem by a high precision measurement of the 1S-2S transition of antihydrogen and a comparison with the precisely known value of the corresponding transition in hydrogen. This thesis presents the achievement of the first step towards this challenging goal: the production of cold antihydrogen itself.
We study quantum mechanically the influence of an external laser field on the antihydrogen (H‾\overline{\mathrm{H}}H) formation cross sections in ground and excited states (2sss,2ppp) via the three-body recombination process inside a dense plasma of antiprotons and positrons, supposed to be the most efficient mechanism for cold and trapped antihydrogen. The plasma screening is considered in the framework of a Debye- H\"uckel potential. The laser polarization is chosen to be parallel to the incident momentum of the passive positron. The modifications due to the presence of the laser field are found to be quite significant both quantitatively and qualitatively for all the states. In the presence of a laser, the H‾\overline{\mathrm{H}}H formation cross sections are found to be suppressed significantly with respect to the field-free situation particularly in the ground state, while the excited state cross sections are in general enhanced at very low incident energies but are again suppressed at higher energies except for some special cases. The sensitivity of the formation cross sections with respect to the Debye length are also studied both in the laser-assisted and in the field-free situations. At very low incident energies, the ground state multiphoton formation is found to enhance with the increase in Debye screening, while the reverse is true for the excited states. These findings should have important implications for future H‾\overline{\mathrm{H}}H studies.
Three body recombination (TBR) process for the formation of antihydrogen () inside a trapped plasma of antiprotons () and positrons (e+), supposed to be the most efficient mechanism for the production of cold and trapped antihydrogen is studied quantum mechanically. Present study also involves a background laser field anticipating further enhancement of the formation cross sections. Significantly large cross sections are obtained in the presence of the field at lower incident energies as compared to the field free ones. Cross sections are enhanced for higher excited states of ().
The formation of antihydrogen atoms from three-body collisions between positronium atoms and antiprotons plays a crucial role in the gravitational behavior of antihydrogen at rest (GBAR) experiment devoted to the measure of the action of gravity on antimatter. One of the main challenges facing this experiment is to find the means for increasing the production of antihydrogens which are produced by the reaction $\overline{p}+\text{Ps}\ensuremath{\rightarrow}\overline{\text{H}}+{e}^{\ensuremath{-}}$ with an extremely low rate. Along these lines, we investigate here the possibility to influence the collision process by using a laser field. A perturbative approach combining the Coulomb-Born approximation for modeling the charged-particle collision and a first-order perturbation theory for describing laser-atom interactions is employed to estimate laser-mediated charge-exchange cross sections. By carefully considering the laser specifications compatible with the experimental constraints, we present an extensive study of the influence of the laser parameters (laser wavelength and intensity) on the cross sections in the energy range of interest for GBAR. We show that under special irradiation conditions the rate of antihydrogen production may be significantly increased by the presence of the laser field.