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:cond-mat/9709038 · Europhysics Letters (EPL)

Shaping an ultracold atomic soliton in a travelling wave laser beam

M Holzmann, Jürgen Audretsch

Published Oct 1, 1997• 9 citations
arXivHTMLPDF

Abstract

An ultracold wave packet of bosonic atoms loaded into a travelling laser wave may form a many-atom soliton. This is disturbed by a homogeneous force field, for example by the inevitable gravitation. The wave packet is accelerated and therefore the laser frequency appears to be chirped in the rest frame of the atoms. We derive the effective nonlinear Schrödinger equation. It shows a time-dependent nonlinearity coefficient which amounts to a damping or antidamping, respectively. The accelerated packet solution remains a soliton which changes its shape adiabatically. Similarly, an active shaping can be obtained in the force-free case by chirping the laser frequency thus representing a way of coherent control of the soliton form. The experimental consequences are discussed.

DOI
10.1209/epl/i1997-00420-8

Related papers

Atomic soliton in a traveling wave laser beam

Weiping Zhang, Daniel F. Walls, Barry C. Sanders

A vector quantum field theory is employed to study the propagation of an ultracold atomic wave packet in a traveling wave laser beam with a Gaussian intensity profile. The collective dipole-dipole correlation induced by photon exchanges between atoms produces a ``Kerr-type'' nonlinearity of atomic waves. We show that such an atomic nonlinearity could result in an atomic soliton under appropriate conditions.

Physical Review Letters•Jan 3, 1994•125 citations

Accelerated guided atomic pulse

Sigurd Dyrting, Weiping Zhang, Barry C. Sanders

The deleterious effects of dispersion on a propagating coherent atomic pulse, along the axis of a traveling-wave laser beam, can be ameliorated by the nonlinear self-interacting force due to dipole-dipole coupling between atoms. We show that a wide atomic pulse with a particular profile can retain its shape during propagation and, moreover, the momentum of the pulse increases due to photon absorption. For the wide soliton case, we demonstrate analytically that the self-interacting atomic force scales inversely with the third power of the pulse width.

Physical Review A•Sep 1, 1997•6 citations

Coherent Nonlinear Matter Wave Dynamics - Bright Atomic Solitons

Bernd Eiermann

The objective of this PhD thesis was the examination of the dynamical behaviour of coherent wave packets realised by Bose-Einstein condensates (BEC) out of 87Rubidium atoms. Their dynamics is mainly affected by linear dispersion due to momentum uncertainty and by nonlinear atomic interaction due to s-wave scattering. The primary objective was the realisation of bright atomic solitons, which represent density distributions with time-independent shape. They only exist if the effects of dispersion and nonlinearity cancel out each other. For 87Rb atoms with repulsive interaction this requires the dispersion of the ensemble to be anomalous. The dispersion of the wave packet can be influenced in sign and in magnitude by superimposing a periodic potential and by changing the quasi-momentum of the atoms. For that purpose an apparatus to produce Bose-Einstein condesates as source of coherent matter waves was build up and characterised. The phase transition was observed as well in magnetic as in optical dipole traps. Experiments related to the dynamic of wave packets were conducted in a twodimensional optical trap retaining the atoms against gravity and allowing them to propagate along the axis of the trap. The periodic potential to influence the dispersion results from two counterpropagating interfering laser beams superimposed to the dipole trap. A first set of experiments demonstrated the possibility to influence the linear dispersion of matter waves by changing the quasi-momentum of the atoms in a periodic potential. In particular wave packets with anomalous dispersion were prepared at the brillouin zone edge in quasi-momentum space. Their behaviour is equivalent to particles with a negative effective mass, which was be confirmed by reversing the time evolution of an expanding wave packet. This demonstration of a negative effective mass of wave packets was an essential prerequisite for the creation of atomic solitons. Their formation was observed having prepared Bose-Einstein condensates of only 1000 atoms. A further set of systematic experiments was performed confirming the solitonic behaviour of the wave packets. This was the first realisation of atomic solitons with repulsive interaction also called Gap-Solitons.

•Jan 1, 2004•0 citations

Laser tweezers for atomic solitons

Alicia V. Carpentier, Juan Belmonte-Beitia, Humberto Michinel +1 more

We describe controllable and precise laser tweezers for Bose–Einstein condensates of ultracold atomic gases. In our configuration, a laser beam is used to locally modify the sign of the scattering length in the vicinity of a trapped BEC. The induced attractive interactions between atoms allow us to extract and transport a controllable number of atoms. We analyze, through numerical simulations, the number of emitted atoms as a function of the width and intensity of the outcoupling beam. We also study different configurations of our system, as the use of moving beams. The main advantage of using the control laser beam to modify the nonlinear interactions in comparison to the usual way of inducing optical forces, i.e. through linear trapping potentials, is to improve the controllability of the outcoupled solitary wave-packet, which opens new possibilities for engineering macroscopic quantum states.

arXiv:0707.4652•Journal of Modern Optics•Oct 10, 2008•25 citations

Suppressing the frequency chirp in optical solitons using coherent effects

Dilson P. Caetano, Jandir M. Hickmann

We report the coherent propagation of optical pulses through a three-level atomic system embedded in a nonlinear dispersive waveguide. We treat the case where an initially chirped soliton in resonance with the pump transition propagates together with a seed without chirp in resonance with the Stokes transition. It is found that the initial chirp is suppressed during the soliton frequency conversion, demonstrating the principle of a frequency converter that produces chirp-free soliton pulses. Numerical solutions of the complete equation set describing our system corroborate our analytical result.

Journal of the Optical Society of America B•Aug 1, 2006•3 citations

Dispersion-free wave packets and feedback solitonic motion in controlled quantum dynamics

Metin Demіralp, HERSCHEL A. RABITZ

This paper considers the feasibility of creating dispersion-free solitary quantum-mechanical wave packets. The analysis is carried out within a general framework of quantum-optimal control theory. A key to the realization of solitary quantum wave packets is the ability to create traveling wave potentials U(x-\ensuremath{\nu}t) with coordinated space and time dependence where \ensuremath{\nu} is a characteristic speed. As an illustration, the case of an atom translating in a designed optical trap is considered. Three examples are treated within this framework: (A) the motion of a dispersion-free traveling bound state, (B) feedback-stabilized solitonic motion, and (C) feedback-stabilized solitonic motion in the presence of auxiliary physical objectives. The quantum solitons of (B) and (C) satisfy a nonlinear Schr\"odinger-type equation with laboratory feedback in the form of an observation of the probability density. This feedback is essential for maintaining the solitonic-type motion. Some generalizations and potential applications of these concepts are also discussed.

Physical Review A•Jan 1, 1997•8 citations
An ultracold wave packet of bosonic atoms loaded into a travelling laser wave may form a many-atom soliton. This is disturbed by a homogeneous force field, for example by the inevitable gravitation. The wave packet is accelerated and therefore the laser frequency appears to be chirped in the rest frame of the atoms. We derive the effective nonlinear Schrödinger equation. It shows a time-dependent nonlinearity coefficient which amounts to a damping or antidamping, respectively. The accelerated packet solution remains a soliton which changes its shape adiabatically. Similarly, an active shaping can be obtained in the force-free case by chirping the laser frequency thus representing a way of coherent control of the soliton form. The experimental consequences are discussed.
The deleterious effects of dispersion on a propagating coherent atomic pulse, along the axis of a traveling-wave laser beam, can be ameliorated by the nonlinear self-interacting force due to dipole-dipole coupling between atoms. We show that a wide atomic pulse with a particular profile can retain its shape during propagation and, moreover, the momentum of the pulse increases due to photon absorption. For the wide soliton case, we demonstrate analytically that the self-interacting atomic force scales inversely with the third power of the pulse width.
The objective of this PhD thesis was the examination of the dynamical behaviour of coherent wave packets realised by Bose-Einstein condensates (BEC) out of 87Rubidium atoms. Their dynamics is mainly affected by linear dispersion due to momentum uncertainty and by nonlinear atomic interaction due to s-wave scattering. The primary objective was the realisation of bright atomic solitons, which represent density distributions with time-independent shape. They only exist if the effects of dispersion and nonlinearity cancel out each other. For 87Rb atoms with repulsive interaction this requires the dispersion of the ensemble to be anomalous. The dispersion of the wave packet can be influenced in sign and in magnitude by superimposing a periodic potential and by changing the quasi-momentum of the atoms. For that purpose an apparatus to produce Bose-Einstein condesates as source of coherent matter waves was build up and characterised. The phase transition was observed as well in magnetic as in optical dipole traps. Experiments related to the dynamic of wave packets were conducted in a twodimensional optical trap retaining the atoms against gravity and allowing them to propagate along the axis of the trap. The periodic potential to influence the dispersion results from two counterpropagating interfering laser beams superimposed to the dipole trap. A first set of experiments demonstrated the possibility to influence the linear dispersion of matter waves by changing the quasi-momentum of the atoms in a periodic potential. In particular wave packets with anomalous dispersion were prepared at the brillouin zone edge in quasi-momentum space. Their behaviour is equivalent to particles with a negative effective mass, which was be confirmed by reversing the time evolution of an expanding wave packet. This demonstration of a negative effective mass of wave packets was an essential prerequisite for the creation of atomic solitons. Their formation was observed having prepared Bose-Einstein condensates of only 1000 atoms. A further set of systematic experiments was performed confirming the solitonic behaviour of the wave packets. This was the first realisation of atomic solitons with repulsive interaction also called Gap-Solitons.
We describe controllable and precise laser tweezers for Bose–Einstein condensates of ultracold atomic gases. In our configuration, a laser beam is used to locally modify the sign of the scattering length in the vicinity of a trapped BEC. The induced attractive interactions between atoms allow us to extract and transport a controllable number of atoms. We analyze, through numerical simulations, the number of emitted atoms as a function of the width and intensity of the outcoupling beam. We also study different configurations of our system, as the use of moving beams. The main advantage of using the control laser beam to modify the nonlinear interactions in comparison to the usual way of inducing optical forces, i.e. through linear trapping potentials, is to improve the controllability of the outcoupled solitary wave-packet, which opens new possibilities for engineering macroscopic quantum states.
We report the coherent propagation of optical pulses through a three-level atomic system embedded in a nonlinear dispersive waveguide. We treat the case where an initially chirped soliton in resonance with the pump transition propagates together with a seed without chirp in resonance with the Stokes transition. It is found that the initial chirp is suppressed during the soliton frequency conversion, demonstrating the principle of a frequency converter that produces chirp-free soliton pulses. Numerical solutions of the complete equation set describing our system corroborate our analytical result.
This paper considers the feasibility of creating dispersion-free solitary quantum-mechanical wave packets. The analysis is carried out within a general framework of quantum-optimal control theory. A key to the realization of solitary quantum wave packets is the ability to create traveling wave potentials U(x-\ensuremath{\nu}t) with coordinated space and time dependence where \ensuremath{\nu} is a characteristic speed. As an illustration, the case of an atom translating in a designed optical trap is considered. Three examples are treated within this framework: (A) the motion of a dispersion-free traveling bound state, (B) feedback-stabilized solitonic motion, and (C) feedback-stabilized solitonic motion in the presence of auxiliary physical objectives. The quantum solitons of (B) and (C) satisfy a nonlinear Schr\"odinger-type equation with laboratory feedback in the form of an observation of the probability density. This feedback is essential for maintaining the solitonic-type motion. Some generalizations and potential applications of these concepts are also discussed.