Southwest Quantum Information and Technology

Observation of stochastic resonance in directed propagation of cold atoms

Presenting Author: Daniel Wingert, Miami University
Contributing Author(s): Alexander Staron, Kefeng Jiang, Ian Dilyard, Casey Scoggins, Ajitha Dharmasiri, Anthony Rapp, Jordan Churi, David Cubero, Samir Bali

We present unambiguous evidence for stochastic resonance in a weakly modulated dissipative optical lattice. Here, stochastic resonance refers to a resonant enhancement in the directed propagation of the confined atoms as we vary the rate of random photon scattering. The lattice is modulated with a weak probe beam. The probe induces a directed propagation of atoms in a direction perpendicular to the probe propagation. By observing the probe transmission spectrum we present evidence that the photon scattering rate at which stochastic resonance occurs is independent of the modulation strength (i.e., the probe intensity) for probe intensities less than 1% of the lattice. We also show that the stochastic resonance frequency can be controlled by varying the lattice well depth. Remarkably, the data agrees well with theory based on a simple F_g = 1/2 to F_e = 3/2 atom without the use of any fitting parameters. A recent novel theory has permitted us to precisely determine the contribution to the directed motion of the atomic density waves excited by the perturbing probe, and how these density fluctuations conspire with the optical pumping rates to create resonant directional atomic propagation within a randomly diffusing cold atom cloud.

(Session 5 : Thursday from 5:00 pm - 7:00 pm)