Storage Ring for Neutral Atoms

Abstract

We have demonstrated a storage ring for ultra-cold neutral atoms. Atoms with mean velocities of 1 m/s corresponding to kinetic energies of ∼100 neV are confined to a 2 cm diameter ring by magnetic forces produced by two current-carrying wires. Up to 10 6 atoms are loaded at a time in the ring, and 7 revolutions are clearly observed. Additionally, we have demonstrated multiple loading of the ring and deterministic manipulation of the longitudinal velocity distribution of the atoms using applied laser pulses. Applications of this ring include large area atom interferometers and cw monochromatic atomic beam generation.03.75. Be, 32.60.+i, 39.10.+j,29.20.Dh Controlling the motional degrees of freedom of neutral atoms has emerged as a major theme in modern atomic physics. The development of laser cooling and related techniques to cool atoms down to the µK regime allows trapping and manipulation of the atomic motion using interactions with the relatively weak electric and magnetic fields available in the laboratory. Complementing the 3-D trapping work, there has been considerable progress recently in developing 2-D magnetic guiding structures for ultra-cold neutral atoms-so-called guided atom optics. Much of this work is motivated by the prospects of coherent de Broglie wave transport for applications including ultrasensitive atomic interferometers and quantum information processing. A variety of simple guides have been developed based on current-carrying wires [1][2][3][4][5], and extensions of these systems have been used to demonstrate atomic beamsplitters [6,7], atom conveyors [8], and magnetic microtraps [8,9].It is compelling to extend these techniques to a ring geometry, and there have been several proposals along these lines [10][11][12], as well as a recent demonstration confining fast polar molecules to an electrostatic ring [13]. These are motivated in part by the prospects of ringbased atomic interferometry and monochromatic atomic beam generation. Similar to optical ring interferometers, the ring geometry offers greater sensitivity through increasing the effective enclosed area of the interferometer both by straightforward enlargement of the ring as well as by employing multiple-orbit interfering trajectories. This is important because the sensitivity of many interactions (e.g. Sagnac rotational phase) is proportional to the enclosed area of the interferometer [14]. This geometry also provides new opportunities to create ultra-cold and monochromatic atomic beams. For example, the ring can be multiply loaded to increase the number of atoms in the ring, and both the longitudinal and transverse velocity distributions of the atoms can be manipulated and cooled in the ring. Finally, highly directional output beams can be created by using a coherent, variable output coupler.In this work, we demonstrate the first storage ring for neutral atoms. Our ring consists of a particularly simple 2-wire magnetic guiding structure. We have developed a technique to successfully transfer atoms to the ring from an external...

Nonadiabatic creation of macroscopic superpositions with strongly correlated one-dimensional bosons in a ring trap

“…Most of the current proposals are based on two-mode Bose-Josephson junctions [3][4][5]. Experimental advances in the realization of ring traps [6][7][8][9][10][11][12] make it realistic to consider other macroscopic superpositions, eg the (collective-mode) superposition of superflow states carrying different values of angular momentum [13][14][15][16], where the coupling between angularmomentum states is provided by a localized barrier which breaks translational invariance; an artificial gauge field (or rotation) [17] gives rise to tunability equivalent to magnetic flux in a SQUID. As a consequence of the ring periodicity, the energy levels of the many-particle system as a function of the flux Φ associated with the artificial gauge field are periodic with period Φ 0 = 2π /m, m * anna.minguzzi@grenoble.cnrs.fr being the atomic mass.…”

Cavity QED with optically transported atoms

“…The experiment begins 1.5 cm above the optical cavity with a laser-cooled sample of 87 Rb atoms collected in a beam-loaded MOT as previously described in [25]. The cavity itself consists of two 1 mm diameter super-polished mirrors with 10 cm radii of curvature separated by 75 µm.…”

Trapping atoms in the vacuum field of a cavity

“…Some of them involve using some external laser fields which exert a confining force to the atom, something that has been successfully realized in recent experiments [19,20,21]. In a far-off resonant trap (FORT) this is achieved by employing a far-off resonant trapping beam along the cavity axis.…”

“…In order to overcome these problems, several strategies to trap an atom in a cavity have been put forward [11,12,13,14,15,16,17,18,19,20,21]. Some of them involve using some external laser fields which exert a confining force to the atom, something that has been successfully realized in recent experiments [19,20,21].…”