Electrodynamic Trapping of Spinless Neutral Atoms with an Atom Chip

Abstract

Three dimensional electrodynamic trapping of neutral atoms has been demonstrated. By applying time-varying inhomogeneous electric fields with micron-sized electrodes, nearly 10 2 strontium atoms in the 1 S0 state have been trapped with a lifetime of 80 ms. In order to design the electrodes, we numerically analyzed the electric field and simulated atomic trajectories in the trap, which showed reasonable agreement with the experiment.PACS numbers: 32.60. +I, 32.80.Pj, 39.25.+k Coherent manipulation of atoms or ions in the vicinity of solid surfaces has attracted increasing interest as a promising tool for quantum information processing (QIP), because of their potential scalability and controllability of atoms or ions that work as qubits [1,2,3,4]. So far, two approaches, i.e., magnetic manipulation of atoms with miniaturized wire traps [5,6] and miniature Paul traps [1] for ions, have been demonstrated. Recent experiments, however, have witnessed that coherence time of these trapped atoms or ions was shortened by electro-magnetic interactions caused by thermal magnetic fields [7,8,9,10] or fluctuating patch potentials [12] appeared on the surface if the distance between the particle and the surface become smaller than 100 µm. To avoid these harmful influences and have a lifetime nearly a second, paramagnetic atoms need to be more than tens of microns apart from metal surfaces at room temperature [7,8,9,10]. A reported heating rate of ions [12] indicated stronger coupling of trapped ions to surface potentials than that of neutral atoms.It has been pointed out that the best candidates for long-lived trap are spinless neutral atoms, which weakly interact with stray fields via the Stark effect [13,14]. Alternatively, material dependence of the trap lifetime has been investigated to reduce thermal magnetic field in magnetic atom-chips [9,10,11]. Electric manipulation of atoms, which allows manipulating spinless neutral atoms in addition to paramagnetic atoms and molecules, may open up a new possibility for scalable quantum systems with long coherence time. In this Letter, we demonstrate three dimensional (3D) electrodynamic trapping of laser cooled Sr atoms in the 1 S 0 state with miniature electrodes fabricated on a glass plate. The very thin electrodes (∼ 40 nm) used in the experiment will significantly reduce thermal magnetic fields near metal surfaces, which would be especially profitable in applying this scheme to paramagnetic atoms.For an applied electric field E(r), the Stark energy is given by U (r) = − 1 2 α|E(r)| 2 . Since the static dipole polarizability α is positive for atoms in stable states, these atoms can be trapped at a local maximum of the electric field strength and behave as a "high-field seeker". However, as the Laplace equation does not allow an electrostatic field to form a maximum in free space, 3D trapping is not possible for a static electric field alone [15]. In addition owing to a small dipole polarizability, rather high electric fields are required for the Stark manipulation of laser-co...

ac electric trapping of neutral atoms

“…Similar trap depths were later obtained for the same molecule with a linear ac trap [12]. In the meantime, Katori and coworkers achieved trapping of about 100 ground-state Sr atoms with a lifetime of 80 ms in a microstructured ac trap on a chip [13]. Recently, we demonstrated trapping of about 10 5 Rb atoms in a 1 mm 3 large and several microkelvins deep trap, with a lifetime of about 5 s [14].…”

Trapping polar molecules in an ac trap

“…This trap is the neutral analog of the linear Paul trap for ions and was recently demonstrated for neutral molecules by Schnell et al ͓25͔. A microstructured version of this trap for neutral atoms was proposed and demonstrated by Katori et al ͓26,27͔.…”

Feasibility of an optical fiber clock

“…The main platforms for compact quantum devices are micro-electromechanical systems [17,18], miniaturized wire traps [19], and, more recently, hollow core optical fibers [20,21]. Here we analyze the feasibility of a "fiber clock"-a device that holds interrogated clock atoms inside a hollow core optical fiber.…”

“…One of the first experimental efforts towards compact optical clocks involved the 3D trapping of an ensemble of Sr atoms in a micron-sized structure [18]. More recently precision spectroscopy of the 1 S 0 -3 P 1 transition of Sr atoms optically trapped inside the Kagome fiber has been performed [21].…”