Probing atom-surface interactions from tunneling-time measurements via rotation-transport on an atom chip

TL;DR

This paper introduces a new method to measure atom-surface interactions by observing tunneling rates of ultracold atoms near a surface, enabling precise extraction of Casimir-Polder force coefficients.

Contribution

It presents a novel combined approach using optical and magnetic traps with surface rotation to measure atom-surface forces via tunneling lifetime analysis.

Findings

Estimated 10% uncertainty in Casimir-Polder coefficient measurement.

Method applicable to various atomic species with magnetic and optical trapping.

Numerical simulations demonstrate feasibility and accuracy of the proposed technique.

Abstract

We propose a novel method to measure the interaction between an ultracold gas of neutral atoms and a surface. This solution combines an optical dipole trap reflected by the surface, a magnetic trap formed by current carrying wires embedded below the surface, and a rotation of the surface itself. It allows to adiabatically transport a $^{87}$Rb BEC from few $\mu$m to few hundred nm of the surface. At such distances, atom-surface interaction strongly affects the trapping potential, causing an increase of the tunneling rate towards the surface. In this paper, we show that the measurement of the lifetime of the cloud and its comparison to a tunneling model will allow to extract the Casimir-Polder (CP) force coefficient in the retarded regime ($c_4$). Our model includes noise-induced heating, calibration biases of experimentally controlled parameters and accuracy of the atom lifetime measurement. Using typical trapping parameters and experimental uncertainties, we numerically estimate the relative uncertainty of $c_4$ to be 10%. This method can be implemented with any atomic species that can be magnetically and optically trapped.