Atom fiber for omnidirectional guiding of cold neutral atoms

Abstract

We present an omnidirectional matter waveguide on an atom chip. The guide is based on a combination of two current-carrying wires and a bias field pointing perpendicular to the chip surface. Thermal atoms are guided for more than two complete turns along a 25-mm-long spiral path (with curve radii as short as 200 microm) at various atom-surface distances (35-450 microm). An extension of the scheme for the guiding of Bose-Einstein condensates is outlined.

OCTBEC—A Matlab toolbox for optimal quantum control of Bose–Einstein condensates

“…From ρ −1 ρ = 1 we find [δρ −1 ]ρ + ρ −1 δρ = 0, which finally yields δρ −1 = −ρ −1 ρρ −1 . Thus, δr = ρ −1 [−δρ r + δρ (2) ]. We then find …”

Classical aspects of ultracold atom wave packet motion through microstructured waveguide bends

“…[26] was adopted here. That is, only multiple wire configurations that do not require external bias fields applied in the plane of the microchip surface are considered [30]. The problems relating to Majorana spin flips during propagation in the zero-field region of such geometries are ignored here, although it is noted that Luo et al [30] have proposed a rotating potential scheme to avoid these losses.…”

“…Specifically, the time-dependent scattering of a wave packet through a circular bend is investigated, neglecting atom-atom interactions. The curved waveguide is a fundamental system that forms the basis for many geometries already experimentally realized, such as multiple circular bends [28], storage rings [29], spiral guides [30], and stadium shaped traps [31]. Note that these experiments all used atoms with relatively high energies, not ground mode atoms, and thus the atomic motion was modelled using Monte Carlo ensembles of classical particles [28][29][30].…”

Manifestations of vortices during ultracold-atom propagation through waveguides

“…These units give an oscillator width ␤ = 1. To provide the typical scale of the SI units involved here, a cloud of 23 Na atoms trapped with a frequency of =2 ϫ 97 Hz [20] corresponds to an oscillator width of ␤ Ϸ 2.13 m. The propagation velocity v z = v 0 = ͱ 2 osc. units (i.e., at the first mode threshold for transverse excitation, E = 1.5 osc.…”

“…[16,17]. That is, we assume a multiple wire configuration that does not require external bias fields applied in the plane of the microchip surface [23], so that the curved waveguide reduces to an effective 2D problem (assuming densities such that atom-atom interactions can be neglected).…”