Quantum Reflection from a Solid Surface at Normal Incidence

Abstract

We observed quantum reflection of ultracold atoms from the attractive potential of a solid surface. Extremely dilute Bose-Einstein condensates of 23Na, with peak density 10(11)-10(12) atoms/cm(3), confined in a weak gravitomagnetic trap were normally incident on a silicon surface. Reflection probabilities of up to 20% were observed for incident velocities of 1-8 mm/s. The velocity dependence agrees qualitatively with the prediction for quantum reflection from the attractive Casimir-Polder potential. Atoms confined in a harmonic trap divided in half by a solid surface exhibited extended lifetime due to quantum reflection from the surface, implying a reflection probability above 50%.

Rabi interferometry and sensitive measurement of the Casimir-Polder force with ultracold gases

“…In particular, once fed with a fermionic/bosonic spin coherent state, the interferometer allows for the accurate measurement of the CasimirPolder force between the atomic sample and a surface. We show that even in the presence of typical experimental noise it is possible to distinguish between thermal and zero-temperature regimes of the Casimir-Polder potential [10], which has not yet been achieved in experiment [11,12,13,14,15]. Moreover, we demonstrate that the Rabi interferometer can further benefit from the use of entangled states as input.…”

“…The possibility to use cold/degenerate atoms for the measurement of forces at small distances has lead to a number of proposals and experiments [11,12,13,14,24,25,26,27]. In [14], the gradient of the Casimir-Polder force was deduced from the shift of the frequency of the collective oscillations of a BEC in a trap put below a surface.…”

Diffuse reflection of a Bose–Einstein condensate from a rough evanescent wave mirror

“…With such a system, one can realize mirrors [6], diffraction gratings [7], 2D traps [8] or waveguides [9]. Experiments involving ultra cold atoms from a BEC at the vicinity of a dielectric surface have recently made significant progress, leading for instance to the realization of a two dimensional BEC [10], to the study of atom-surface reflection in the quantum regime [11], and to sensitive measurements of adsorbate-induced surface polarization [12] and of the Van der Waals/Casimir-Polder surface interaction [13]. .…”

Two-dimensional simulation of quantum reflection

“…the reflection of a quantum object in the absence of a classical turning point [1,2], has attracted an increasing number of studies, triggered by the developments in the field of matter-wave optics for a variety of experimental platforms [3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19].…”