Scattering and absorption of ultracold atoms by nanotubes

Abstract

We investigate theoretically how cold atoms, including Bose-Einstein condensates, are scattered from, or absorbed by, nanotubes with a view to analysing recent experiments. In particular, we consider the role of potential strength, quantum reflection, atomic interactions and tube vibrations on atom loss rates. Lifshitz theory calculations deliver a significantly stronger scattering potential than that found in experiment and we discuss possible reasons for this. We found that the scattering potential for dielectric tubes can be calculated to a good approximation using a modified pairwise summation approach, which is efficient and easily extendable to arbitrary geometries. Quantum reflection of atoms from a nanotube may become a significant factor at low temperatures, especially for non-metallic tubes. Interatomic interactions are shown to increase the rate at which atoms are lost to the nanotube and lead to non-trivial dynamics. Thermal nanotube vibrations do not significantly increase loss rates or reduce condensate fractions, but lower frequency oscillations can dramatically heat the cloud.

Evaporative cooling of cold atoms at surfaces

“…There is potential to use such systems as quantum memory devices [13][14][15], precision measurement devices [16][17][18][19] and even rewritable electronic systems [20]. More recently, there have been proposals to use cold atoms to cool nanoscaled solid objects [21,22]; ion cooling using neutral atoms has already been demonstrated [23,24].…”

Sensing microwave photons with a Bose–Einstein condensate

“…The distance d between the two systems has to be chosen in a way to maximize the coupling while avoiding the effect of van der Waals forces [18,19] between the trapped atoms and the CPW (d 0 1 µm). At a distance of d > (d 0 + a) in the negative y direction, i.e., at the center of the BEC (y = 0), according to Eqs.…”

Immersing carbon nanotubes in cold atomic gases

“…Recent experiments [29,36], have provided evidence that the dominant contribution is given by an inverse power-law term ∼ C 5 /ρ 5 . However, in order to keep the model flexible, we approximate the Casimir-Polder potential as an inverse power series…”

“…Polarizable particles in front of surfaces are affected by Casimir-Polder potentials [30][31][32]. The measurement of such minute forces with ultra-cold atoms is of high interest [33][34][35][36]. In particular, the interaction and trapping of atoms in front of nano-tubes has been explored [37,38].…”