Quantum Point Contacts for Neutral Atoms

We show that the conductance of atoms through a tightly confining waveguide constriction is quantized in units of ${\lambda }_{\mathrm{dB}}^2/\pi$, where ${\lambda }_{\mathrm{dB}}$ is the de Broglie wavelength of the incident atoms. Such a constriction forms the atom analog of an electron quantum point contact and is an example of quantum transport of neutral atoms in an aperiodic system. We present a practical constriction geometry that can be realized using a microfabricated magnetic waveguide, and discuss how a pair of such constrictions can be used to study the quantum statistics of weakly interacting gases in small traps.