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

Chinese Journal of Lasers

A Novel Ac Electro-magnetic Trap for Neutral Atoms

Xu Li-Fang

Published Jan 1, 2001• 0 citations
OpenAlex

Abstract

In this article, a novel ac electro-magnetic trap for neutral atoms is proposed, which is based on the interaction of a magnetic dipole moment of trapped atoms with both an ac quadruple magnetic field in the transverse direction and a dc-bias magnetic field along the axial direction. The result shows that this is an ideal strong field-seeking trap for cold atoms. An atom guide with radial trapping potential over 1.2 mK is obtained and the guided atoms can be confined in a small region of r～50 μm. With changing the distribution of the bias magnetic field, an ac magneitc trap of cold atoms with axial potential depth 0.5 mK and radial potential 0.6 mK can be got, which is high enough to trap nearly all atoms with a temperature of ～120 μK.

Related papers

A Proposal for Guiding and Trapping of Cold Atoms in the AC Field of Current‐Carrying Wires

Lifang Xu, Jianping Yin, Yuzhu Wang

Abstract We propose a novel ac electro‐magnetic guiding and trapping of cold neutral atoms, which is based on the interaction of a magnetic dipole moment of guided and trapped atom with both an ac quadrupole magnetic field in the trans verse direction and a dc‐bias magnetic field along the guiding axis. The time‐averaged magnetic potential and force for the atoms are calculated. And the results show that the potential is high enough to collect and guide nearly all of the cold atoms from a standard magneto‐optical trap with a temperature of ∼ 120 μK.

Journal of the Chinese Chemical Society•Jun 1, 2001•1 citation

Magnetic trapping of neutral atoms

Thomas H. Bergeman, Harold J. Metcalf

Magnetic trapping of laser-cooled neutral atoms has been demonstrated at NBS and is progressing in other laboratories. Confinement of any object requires exchanging kinetic for potential energy, and for neutral atoms, this necessarily derives from shifts of internal energy levels. This is implemented through the force experienced by the atomic magnetic moment in a carefully designed, highly inhomogeneous field. Since magnetic fields of convenient strength can shift atomic energy levels by only a few gigahertz (temperature ≌ 0.1 K), neutral atom traps are very shallow and must be loaded with very cold atoms. We present some motivations for using magnetic traps and then discuss the constraints and optimal configurations of various arrangements. For example, no trap can be isotropic. Next we discuss both the classical and quantum mechanical motions of trapped atoms. These motions are important for at least two reasons: First, several schemes under study for further cooling depend on knowing the position and velocity of the atoms, as well as the vector field at each point along the orbit. Second, magnetic traps depend on the atomic moment remaining aligned with the field as the atom orbits in the trap, and this precludes rapid motion through a low-field region.

International Laser Science Conference•Jan 1, 1986•0 citations

Magnetic trapping of neutral atoms

T. H. Bergeman, H. Metcalf

We have been studying the use of inhomogeneous magnetic fields for the trapping of neutral atoms via the interaction with their magnetic moments. Apart from gravitational forces (which may turn out to be of great importance in atom traps), only electromagnetic forces are of real interest for trapping neutral atoms, and these forces must necessarily arise from the interaction of multipole moments and inhomogeneous fields. In this paper we restrict ourselves to static traps and magnetic dipoles, even though optical, quasi‐static, and Stark effect traps have been discussed. We present some discussion of the field configurations that might be used, of the motion of ‘‘warm’’ trapped atoms (about 1 K), and of the states of ‘‘cold’’ trapped atoms (about 0.1 μK). The basic scale of the interaction is set by the ratio of the Bohr magneton to the Boltzmann constant, about 1.5 Tesla/Kelvin.

AIP conference proceedings•Jan 1, 1987•1 citation

Controllable Double-Well Magneto-Optical Trap for Neutral Atoms

Yun Min, Yin Jian-Ping

We propose a novel controllable double-well magneto-optical trap (MOT) by using a square current-carrying wire and a bias magnetic field. The spatial distributions of the magnetic fields and their gradients are calculated, and the results show that the proposed trap has double magnetic wells with two centres of zero magnetic field and can be continuously evolved as a single-well trap by reducing the current in the wire or increasing the bias field, which can be used to realize a controllable double-well MOT, even to prepare one- and two-dimensional arrays of magneto-optical lattices on the surface of an atom chip. We also estimate the number (~107) and temperature (~260 μK) of trapped cold atoms in our MOT.

Chinese Physics Letters•Jul 30, 2004•3 citations

Controllable cold atom beam splitter based on parallel current-carrying wires and bias magnetic field

Liu Nan-Chun

A novel controllable cold neutral atom guiding scheme based on parallel current-carrying wires and bias magnetic field is proposed.Magnetic field distribution in cross-section at different transverse bias field B_(bx) is calculated.The centre of magnetic traps is discussed.Single-channel and double-channel magnetic guiding can be realized.Based on this scheme,an atom beam splitter,which has adjustable splitting ratio, is designed by adding a longitudinal magnetic bias field B_(by).The transverse distribution of magnetic trap is calculated,and the magnetic contour plane of the splitter is shown.By using the classical Monte-Carlo method,the splitting process is simulated,and this scheme is validated by the simulation results.Splitting ratio between left and right guide changes from 0.9/0.1 to 0.1/0.9 when longitudinal magnetic bias field B_(by) changes from -0.005 G to 0.005 G.

Chinese Journal of Quantum Electronics•Jan 1, 2011•0 citations

Permanent magnet trap for cold atoms

J. J. Tollett, C. C. Bradley, Charles A. Sackett +1 more

We report the trapping of neutral atoms in a permanent magnet trap. Approximately 1\ifmmode\times\else\texttimes\fi{}${10}^{8}$ ground-state lithium atoms have been confined in a nonzero magnetic-field minimum produced by six permanent magnets in an Ioffe configuration. These atoms have a kinetic temperature of 1.1 mK and a peak density of approximately 3\ifmmode\times\else\texttimes\fi{}${10}^{9}$ ${\mathrm{cm}}^{\mathrm{\ensuremath{-}}3}$. The trapped-atom lifetime is 240 s, limited by collisions with background gas. This trap provides an environment in which quantum-statistical effects, atomic collisions, and other ultralow-temperature phenomena can be studied.

Physical Review A•Jan 1, 1995•54 citations
In this article, a novel ac electro-magnetic trap for neutral atoms is proposed, which is based on the interaction of a magnetic dipole moment of trapped atoms with both an ac quadruple magnetic field in the transverse direction and a dc-bias magnetic field along the axial direction. The result shows that this is an ideal strong field-seeking trap for cold atoms. An atom guide with radial trapping potential over 1.2 mK is obtained and the guided atoms can be confined in a small region of r～50 μm. With changing the distribution of the bias magnetic field, an ac magneitc trap of cold atoms with axial potential depth 0.5 mK and radial potential 0.6 mK can be got, which is high enough to trap nearly all atoms with a temperature of ～120 μK.
Abstract We propose a novel ac electro‐magnetic guiding and trapping of cold neutral atoms, which is based on the interaction of a magnetic dipole moment of guided and trapped atom with both an ac quadrupole magnetic field in the trans verse direction and a dc‐bias magnetic field along the guiding axis. The time‐averaged magnetic potential and force for the atoms are calculated. And the results show that the potential is high enough to collect and guide nearly all of the cold atoms from a standard magneto‐optical trap with a temperature of ∼ 120 μK.
Magnetic trapping of laser-cooled neutral atoms has been demonstrated at NBS and is progressing in other laboratories. Confinement of any object requires exchanging kinetic for potential energy, and for neutral atoms, this necessarily derives from shifts of internal energy levels. This is implemented through the force experienced by the atomic magnetic moment in a carefully designed, highly inhomogeneous field. Since magnetic fields of convenient strength can shift atomic energy levels by only a few gigahertz (temperature ≌ 0.1 K), neutral atom traps are very shallow and must be loaded with very cold atoms. We present some motivations for using magnetic traps and then discuss the constraints and optimal configurations of various arrangements. For example, no trap can be isotropic. Next we discuss both the classical and quantum mechanical motions of trapped atoms. These motions are important for at least two reasons: First, several schemes under study for further cooling depend on knowing the position and velocity of the atoms, as well as the vector field at each point along the orbit. Second, magnetic traps depend on the atomic moment remaining aligned with the field as the atom orbits in the trap, and this precludes rapid motion through a low-field region.
We have been studying the use of inhomogeneous magnetic fields for the trapping of neutral atoms via the interaction with their magnetic moments. Apart from gravitational forces (which may turn out to be of great importance in atom traps), only electromagnetic forces are of real interest for trapping neutral atoms, and these forces must necessarily arise from the interaction of multipole moments and inhomogeneous fields. In this paper we restrict ourselves to static traps and magnetic dipoles, even though optical, quasi‐static, and Stark effect traps have been discussed. We present some discussion of the field configurations that might be used, of the motion of ‘‘warm’’ trapped atoms (about 1 K), and of the states of ‘‘cold’’ trapped atoms (about 0.1 μK). The basic scale of the interaction is set by the ratio of the Bohr magneton to the Boltzmann constant, about 1.5 Tesla/Kelvin.
We propose a novel controllable double-well magneto-optical trap (MOT) by using a square current-carrying wire and a bias magnetic field. The spatial distributions of the magnetic fields and their gradients are calculated, and the results show that the proposed trap has double magnetic wells with two centres of zero magnetic field and can be continuously evolved as a single-well trap by reducing the current in the wire or increasing the bias field, which can be used to realize a controllable double-well MOT, even to prepare one- and two-dimensional arrays of magneto-optical lattices on the surface of an atom chip. We also estimate the number (~107) and temperature (~260 μK) of trapped cold atoms in our MOT.
A novel controllable cold neutral atom guiding scheme based on parallel current-carrying wires and bias magnetic field is proposed.Magnetic field distribution in cross-section at different transverse bias field B_(bx) is calculated.The centre of magnetic traps is discussed.Single-channel and double-channel magnetic guiding can be realized.Based on this scheme,an atom beam splitter,which has adjustable splitting ratio, is designed by adding a longitudinal magnetic bias field B_(by).The transverse distribution of magnetic trap is calculated,and the magnetic contour plane of the splitter is shown.By using the classical Monte-Carlo method,the splitting process is simulated,and this scheme is validated by the simulation results.Splitting ratio between left and right guide changes from 0.9/0.1 to 0.1/0.9 when longitudinal magnetic bias field B_(by) changes from -0.005 G to 0.005 G.
We report the trapping of neutral atoms in a permanent magnet trap. Approximately 1\ifmmode\times\else\texttimes\fi{}108{10}^{8}108 ground-state lithium atoms have been confined in a nonzero magnetic-field minimum produced by six permanent magnets in an Ioffe configuration. These atoms have a kinetic temperature of 1.1 mK and a peak density of approximately 3\ifmmode\times\else\texttimes\fi{}109{10}^{9}109 ${\mathrm{cm}}^{\mathrm{\ensuremath{-}}3}$. The trapped-atom lifetime is 240 s, limited by collisions with background gas. This trap provides an environment in which quantum-statistical effects, atomic collisions, and other ultralow-temperature phenomena can be studied.