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-Atom Optics Downunder (QAO)

Rotational Bragg Scattering: Spinning Atoms With the Orbital Angular Momentum of Light

William D. Phillips, Mikkel F. Andersen, Pierre Cladé, Kristian Helmerson, Vasant Natarajan A, Anand K. Ramanathan, Changhyun Ryu, Alipasha Vaziri

Published Jan 1, 2007• 0 citations
Publisher

Abstract

We demonstrate the coherent, quantized transfer of the orbital angular momentum of light to a Bose-Einstein condensate of sodium atoms by means of a stimulated, two-photon transition between the static, non-rotating BEC and a rotating state moving with the linear momentum of two photons. By reversing the transfer of linear momentum, without any angular momentum, we create either vortex states (in a simply connected trap) or persistent atom currents (in a toroidal trap). The persistent current in the toroidal trap lasts about 20 times longer than a vortex under similar conditions in the simply connected trap.

DOI
10.1364/qao.2007.qma1

Related papers

Vortices and Persistent Currents: Rotating a Bose-Einstein Condensate Using Photons with Orbital Angular Momentum

Kristian Helmerson, Mikkel F. Andersen, Pierre Cladé +5 more

We describe the coherent transfer of the orbital angular momentum of a photon to an atom in quantized units of ℏ, using a 2-photon stimulated Raman process with Laguerre-Gaussian beams to generate an atomic vortex state in a Bose-Einstein condensate (BEC) of sodium atoms. We show that the process is coherent by creating superpositions of different vortex states, where the relative phase between the states is determined by the relative phases of the optical fields. We use this technique to generate circular flow of a BEC confined in a toriodal shaped trap. We measure that the flow of atoms persists for up to 10 seconds, which we interpret as the first evidence of persistent currents in a superfluid Bose gas.

Topologica•Jan 1, 2009•6 citations

Rotating a Bose-Einstein condensate using photons with orbital angular momentum

Kristian Helmerson, Mikkel F. Andersen, Changhyun Ryu +5 more

We demonstrate the coherent transfer of the orbital angular momentum of a photon to an atom in quantized units of h, using a 2-photon stimulated Raman process with Laguerre-Gaussian beams to generate an atomic vortex state in a Bose-Einstein condensate of sodium atoms. We show that the process is coherent by creating superpositions of different vortex states, where the relative phase between the states is determined by the relative phases of the optical fields. Furthermore, we create vortices of charge 2 by transferring to each atom the orbital angular momentum of two photons. We subsequently use our technique to induce rotation of the condensate confined in an asymmetric, ring-shaped hybrid optical and magnetic trap. We observe the cloud rotating for up to 13 seconds, due to the superfluid character of the condensate.

Proceedings of SPIE, the International Society for Optical Engineering/Proceedings of SPIE•Aug 31, 2006•2 citations

Quantized Rotation of Atoms from Photons with Orbital Angular Momentum

Mikkel F. Andersen, Changhyun Ryu, Pierre Cladé +4 more

We demonstrate the coherent transfer of the orbital angular momentum of a photon to an atom in quantized units of variant Planck's over 2pi, using a 2-photon stimulated Raman process with Laguerre-Gaussian beams to generate an atomic vortex state in a Bose-Einstein condensate of sodium atoms. We show that the process is coherent by creating superpositions of different vortex states, where the relative phase between the states is determined by the relative phases of the optical fields. Furthermore, we create vortices of charge 2 by transferring to each atom the orbital angular momentum of two photons.

arXiv:quant-ph/0607171•Physical Review Letters•Oct 26, 2006•589 citations

Rotating a Bose-Einstein Condensate Using Photons with Orbital Angular Momentum

Kristian Helmerson, Mikkel F. Andersen, Changhyun Ryu +4 more

We demonstrate the coherent transfer of the orbital angular momentum of photons to atoms using a stimulated 2-photon Raman process with Laguerre-Gaussian beams. The process is used to create superpositions of rotational (vortex) atomic states.

Frontiers in Optics•Jan 1, 2006•1 citation

Observation of Persistent Flow of a Bose-Einstein Condensate in a Toroidal Trap

Changhyun Ryu, Mikkel F. Andersen, Pierre Cladé +3 more

We have observed the persistent flow of Bose-condensed atoms in a toroidal trap. The flow persists without decay for up to 10 s, limited only by experimental factors such as drift and trap lifetime. The quantized rotation was initiated by transferring one unit variant Planck's over 2pi of the orbital angular momentum from Laguerre-Gaussian photons to each atom. Stable flow was only possible when the trap was multiply connected, and was observed with a Bose-Einstein condensate fraction as small as 20%. We also created flow with two units of angular momentum and observed its splitting into two singly charged vortices when the trap geometry was changed from multiply to simply connected.

arXiv:0709.0012•Physical Review Letters•Dec 28, 2007•553 citations

Observation of Persistent Flow of a Bose-Einstein Condensate in a Toroidal Trap

Kristian Helmerson, Changhyun Ryu, Mikkel F. Andersen +4 more

We have observed the persistent flow of Bose-condensed atoms in a toroidal trap. The flow persists without decay for up to 10 s, and was initiated by transferring one unit, ħ, of the orbital angular momentum from Laguerre-Gaussian photons to each atom. Stable flow was only possible when the trap was multiply-connected, and was observed with a BEC fraction as small as 15%. We also created flow with two units of angular momentum, and observed its splitting into two singly-charged vortices when the trap geometry was changed from multiply- to simply-connected.

Quantum-Atom Optics Downunder (QAO)•Jan 1, 2007•18 citations
We demonstrate the coherent, quantized transfer of the orbital angular momentum of light to a Bose-Einstein condensate of sodium atoms by means of a stimulated, two-photon transition between the static, non-rotating BEC and a rotating state moving with the linear momentum of two photons. By reversing the transfer of linear momentum, without any angular momentum, we create either vortex states (in a simply connected trap) or persistent atom currents (in a toroidal trap). The persistent current in the toroidal trap lasts about 20 times longer than a vortex under similar conditions in the simply connected trap.
We describe the coherent transfer of the orbital angular momentum of a photon to an atom in quantized units of ℏ, using a 2-photon stimulated Raman process with Laguerre-Gaussian beams to generate an atomic vortex state in a Bose-Einstein condensate (BEC) of sodium atoms. We show that the process is coherent by creating superpositions of different vortex states, where the relative phase between the states is determined by the relative phases of the optical fields. We use this technique to generate circular flow of a BEC confined in a toriodal shaped trap. We measure that the flow of atoms persists for up to 10 seconds, which we interpret as the first evidence of persistent currents in a superfluid Bose gas.
We demonstrate the coherent transfer of the orbital angular momentum of a photon to an atom in quantized units of h, using a 2-photon stimulated Raman process with Laguerre-Gaussian beams to generate an atomic vortex state in a Bose-Einstein condensate of sodium atoms. We show that the process is coherent by creating superpositions of different vortex states, where the relative phase between the states is determined by the relative phases of the optical fields. Furthermore, we create vortices of charge 2 by transferring to each atom the orbital angular momentum of two photons. We subsequently use our technique to induce rotation of the condensate confined in an asymmetric, ring-shaped hybrid optical and magnetic trap. We observe the cloud rotating for up to 13 seconds, due to the superfluid character of the condensate.
We demonstrate the coherent transfer of the orbital angular momentum of a photon to an atom in quantized units of variant Planck's over 2pi, using a 2-photon stimulated Raman process with Laguerre-Gaussian beams to generate an atomic vortex state in a Bose-Einstein condensate of sodium atoms. We show that the process is coherent by creating superpositions of different vortex states, where the relative phase between the states is determined by the relative phases of the optical fields. Furthermore, we create vortices of charge 2 by transferring to each atom the orbital angular momentum of two photons.
We have observed the persistent flow of Bose-condensed atoms in a toroidal trap. The flow persists without decay for up to 10 s, limited only by experimental factors such as drift and trap lifetime. The quantized rotation was initiated by transferring one unit variant Planck's over 2pi of the orbital angular momentum from Laguerre-Gaussian photons to each atom. Stable flow was only possible when the trap was multiply connected, and was observed with a Bose-Einstein condensate fraction as small as 20%. We also created flow with two units of angular momentum and observed its splitting into two singly charged vortices when the trap geometry was changed from multiply to simply connected.
We have observed the persistent flow of Bose-condensed atoms in a toroidal trap. The flow persists without decay for up to 10 s, and was initiated by transferring one unit, ħ, of the orbital angular momentum from Laguerre-Gaussian photons to each atom. Stable flow was only possible when the trap was multiply-connected, and was observed with a BEC fraction as small as 15%. We also created flow with two units of angular momentum, and observed its splitting into two singly-charged vortices when the trap geometry was changed from multiply- to simply-connected.