© 2026 Aqora Quantum S.A.S.

Terms Privacy Legal Notice

arXiv:0806.0212 · Physical Review A

Paired-atom laser beams created via four-wave mixing

R. G. Dall, L. J. Byron, Andrew G. Truscott, G. R. Dennis, Mattias Johnsson, J. J. Hope

Published Jan 9, 2009• 42 citations

Abstract

A method to create paired-atom laser beams from a metastable helium atom laser via four-wave mixing is demonstrated. Radio-frequency outcoupling is used to extract atoms from a Bose-Einstein condensate near the center of the condensate and initiate scattering between trapped and untrapped atoms. The unequal strengths of the interactions for different internal states allows an energy-momentum resonance which leads to the creation of pairs of atoms scattered from the zero-velocity condensate. The resulting scattered beams are well separated from the main atom laser in the two-dimensional transverse atom laser profile. Numerical simulations of the system are in good agreement with the observed atom laser spatial profiles and indicate that the scattered beams are generated by a four-wave mixing process, suggesting that the beams are correlated.

DOI: 10.1103/physreva.79.011601

Related papers

Generation of Macroscopic Pair-Correlated Atomic Beams by Four-Wave Mixing in Bose-Einstein Condensates

J. M. M. J. Vogels, K. Xu, Wolfgang Ketterle

By colliding two Bose-Einstein condensates, we have observed strong bosonic stimulation of the elastic scattering process. When a weak input beam was applied as a seed, it was amplified by a factor of 20. This large gain atomic four-wave mixing resulted in the generation of two macroscopically occupied pair-correlated atomic beams.

arXiv:cond-mat/0203286•Physical Review Letters•Jun 24, 2002•131 citations

Quantum theory of an atom laser originating from a Bose-Einstein condensate or a Fermi gas in the presence of gravity

Tobias Kramer, Mirta Rodríguez

We present a three-dimensional quantum-mechanical theory of radio-frequency-outcoupled atom lasers from trapped atomic gases in the presence of the gravitational force. Predictions for the total outcoupling rate as a function of the radio frequency and for the beam wave function are given. We establish a sum rule for the energy-integrated outcoupling, which leads to a separate determination of the coupling strength between the atoms and radiation field. For a noninteracting Bose-Einstein condensate analytic solutions are derived which are subsequently extended to include the effects of atomic interactions. The interactions enhance interference effects in the beam profile and modify the outcoupling rate of the atom laser. We provide a complete quantum-mechanical solution which is in line with experimental findings and allows us to determine the validity of commonly used approximative methods. We also extend the formalism to a fermionic atom laser and analyze the effect of superfluidity on the outcoupling of atoms.

arXiv:cond-mat/0604464•Physical Review A•Jul 14, 2006•18 citations

Properties of a Raman atom-laser output coupler

Mark Edwards, David A. Griggs, Philip L Holman +3 more

We have studied the characteristics of an atom laser created by removing atoms from a Bose-Einstein condensate (BEC) via a two-photon Raman process. In contrast with outcoupling by RF transitions, Raman outcoupling offers spatial selectivity within the condensate and delivers significant momentum transfer to the outcoupled atoms. We develop a version of zero-temperature mean-field theory for BECs which includes the internal state of the atom and the effect of laser fields focused into the cloud. For a model condensate we find that the outcoupled matter wave develops sharp peaks at spatial positions where the two-photon Raman process is resonant with the hyperfine splitting of the atomic ground state. As time proceeds the width of the outcoupled wave expands and a steady stream of matter waves travels outside the condensate volume.

Journal of Physics B Atomic Molecular and Optical Physics•Jan 1, 1999•30 citations

Theory Of A Pulsed RF Atom Laser

J. Schneider, Axel Schenzle

An atom laser based on RF-outcoupling can be operated in a coherently pulsed way by using two radio frequencies. Such a two-mode atom laser can be described by coupled Gross-Pitaevskii equations which are valid for very low temperatures (T≈0). We have derived analytic expressions for the output rate and the visibility of the pulsed atomic beam in the weak coupling regime. A comparison between the analytical and numerical results shows a good agreement. This proves our assumption that the outcoupling process may be seen as the coherent outcoupling of two independent atomic beams. Though our model is only one-dimensional, we expect also a good agreement with the full 3D situation of experiment; the estimate for the value of the output rate might be only in the right order of magnitude16. Summarizing, the manipulation of trapped Bose condensates with electromagnetic waves opens a wide new area for the field of coherent atom optics.

Kluwer Academic Publishers eBooks•Dec 11, 2005•0 citations

Atomic four-wave mixing via condensates collisions

A. Perrin, C. M. Savage, Valentina Krachmalnicoff +4 more

We perform first principles quantum simulations of atomic four-wave mixing via a collision of two Bose-Einstein condensates of metastable helium atoms. We analyse the collinear and back-to-back pair correlations of atoms on the s-wave scattering halo. The results provide qualitative and quantitative understanding of the recent experiments at Orsay [A. Perrin et al., arXiv: 0704.3047].

Quantum-Atom Optics Downunder (QAO)•Jan 1, 2007•1 citation

Atomic four-wave mixing via condensate collisions

A. Perrin, Craig M. Savage, Denis Boiron +3 more

We perform a theoretical analysis of atomic four-wave mixing via a collision of two Bose–Einstein condensates of metastable helium atoms, and compare the results to a recent experiment. We calculate atom–atom pair correlations within the scattering halo produced spontaneously during the collision. We also examine the expected relative number squeezing of atoms on the sphere. The analysis includes first-principles quantum simulations using the positive P -representation method. We develop a unified description of the experimental and simulation results.

arXiv:0712.2145•New Journal of Physics•Apr 30, 2008•43 citations

A method to create paired-atom laser beams from a metastable helium atom laser via four-wave mixing is demonstrated. Radio-frequency outcoupling is used to extract atoms from a Bose-Einstein condensate near the center of the condensate and initiate scattering between trapped and untrapped atoms. The unequal strengths of the interactions for different internal states allows an energy-momentum resonance which leads to the creation of pairs of atoms scattered from the zero-velocity condensate. The resulting scattered beams are well separated from the main atom laser in the two-dimensional transverse atom laser profile. Numerical simulations of the system are in good agreement with the observed atom laser spatial profiles and indicate that the scattered beams are generated by a four-wave mixing process, suggesting that the beams are correlated.

We present a three-dimensional quantum-mechanical theory of radio-frequency-outcoupled atom lasers from trapped atomic gases in the presence of the gravitational force. Predictions for the total outcoupling rate as a function of the radio frequency and for the beam wave function are given. We establish a sum rule for the energy-integrated outcoupling, which leads to a separate determination of the coupling strength between the atoms and radiation field. For a noninteracting Bose-Einstein condensate analytic solutions are derived which are subsequently extended to include the effects of atomic interactions. The interactions enhance interference effects in the beam profile and modify the outcoupling rate of the atom laser. We provide a complete quantum-mechanical solution which is in line with experimental findings and allows us to determine the validity of commonly used approximative methods. We also extend the formalism to a fermionic atom laser and analyze the effect of superfluidity on the outcoupling of atoms.

We have studied the characteristics of an atom laser created by removing atoms from a Bose-Einstein condensate (BEC) via a two-photon Raman process. In contrast with outcoupling by RF transitions, Raman outcoupling offers spatial selectivity within the condensate and delivers significant momentum transfer to the outcoupled atoms. We develop a version of zero-temperature mean-field theory for BECs which includes the internal state of the atom and the effect of laser fields focused into the cloud. For a model condensate we find that the outcoupled matter wave develops sharp peaks at spatial positions where the two-photon Raman process is resonant with the hyperfine splitting of the atomic ground state. As time proceeds the width of the outcoupled wave expands and a steady stream of matter waves travels outside the condensate volume.

An atom laser based on RF-outcoupling can be operated in a coherently pulsed way by using two radio frequencies. Such a two-mode atom laser can be described by coupled Gross-Pitaevskii equations which are valid for very low temperatures (T≈0). We have derived analytic expressions for the output rate and the visibility of the pulsed atomic beam in the weak coupling regime. A comparison between the analytical and numerical results shows a good agreement. This proves our assumption that the outcoupling process may be seen as the coherent outcoupling of two independent atomic beams. Though our model is only one-dimensional, we expect also a good agreement with the full 3D situation of experiment; the estimate for the value of the output rate might be only in the right order of magnitude16. Summarizing, the manipulation of trapped Bose condensates with electromagnetic waves opens a wide new area for the field of coherent atom optics.

We perform a theoretical analysis of atomic four-wave mixing via a collision of two Bose–Einstein condensates of metastable helium atoms, and compare the results to a recent experiment. We calculate atom–atom pair correlations within the scattering halo produced spontaneously during the collision. We also examine the expected relative number squeezing of atoms on the sphere. The analysis includes first-principles quantum simulations using the positive P -representation method. We develop a unified description of the experimental and simulation results.