One atomic beam as a detector of classical harmonic vibrations with micro amplitudes and low frequencies

Abstract

We propose a simplest detector of harmonic vibrations with micro amplitudes and low frequencies, i.e. a detector consisting of one atomic beam. Here, the atomic beam is induced by a plane harmonic wave and has classical collective harmonic vibrations, whose vibrant directions are perpendicular to the wave vectors of the atomic beam. Compared with a detector consisting of an atomic Mach-Zehnder interferometer, the new detector has two advantages: (1) it is suitable for the detection of harmonic vibrations induced either by a longitudinal plane harmonic wave or by using a transverse plane harmonic wave: (2) the quantum noise fluctuation of the atomic beam is exactly zero. We present the principle for detecting classical harmonic vibrations with micro amplitudes and low frequencies by using the new detector. The frequency of a classical harmonic vibration with a micro amplitude can be evaluated by measuring the variations in the mean numbers of atoms arriving at the atomic detector.