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(dB)(2)/pi, where lambda(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 he 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.