Measurements and analysis of response function of cold atoms in optical molasses

Abstract

We report our experimental measurements and theoretical analysis of the position response function of a cloud of cold atoms residing in the viscous medium of an optical molasses and confined by a magneto-optical trap (MOT). We measure the position response function by applying a transient homogeneous magnetic field as a perturbing force. We observe a transition from a damped oscillatory motion to an over-damped relaxation, stemming from a competition between the viscous drag provided by the optical molasses and the restoring force of the MOT. Our observations are in both qualitative and quantitative agreement with the predictions of a theoretical model based on the Langevin equation. As a consistency check, and as a prototype for future experiments, we also study the free diffusive spreading of the atomic cloud in our optical molasses with the confining magnetic field of the MOT turned off. We find that the measured value of the diffusion coefficient agrees with the value predicted by our Langevin model, using the damping coefficient. The damping coefficient was deduced from our measurements of the position response function at the same temperature.

References in corpus (16)

• A quantum gas microscope - detecting single atoms in a Hubbard regime optical lattice
• Single-Atom Resolved Fluorescence Imaging of an Atomic Mott Insulator
• Observation of anomalous diffusion and fractional self-similarity in one dimension
• Non-Hermitian Linear Response Theory
• From the area under the Bessel excursion to anomalous diffusion of cold atoms
• Atomtronics-enabled Quantum Technologies
• Theory of fractional-Lévy kinetics for cold atoms diffusing in optical lattices
• Observation of individual tracer atoms in an ultracold dilute gas
• Linear Response Theory and Optical Conductivity of Floquet Topological Insulators
• Laser Cooling of Radium Ions
• Three-dimensional laser cooling at the Doppler limit
• Quantum Brownian Motion: Drude and Ohmic Baths as Continuum Limits of the Rubin Model
• Brownian motion at absolute zero
• Diffusion of cold atomic gases in the presence of an optical speckle potential
• Langevin equation of collective modes of Bose-Einstein condensates in traps
• A quantum diffusion law

Cited by in corpus (6)

• A Nernst heat theorem for nonequilibrium jump processes
• Quantum Langevin dynamics of a charged particle in a magnetic field : Response function, position-velocity and velocity autocorrelation functions
• Fast loading of a cold mixture of Sodium and Potassium atoms from compact and versatile cold atomic beam sources
• Long Time Tails in Quantum Brownian Motion of a charged particle in a magnetic field
• Effect of light-assisted tunable interaction on the position response function of cold atoms
• Non-resonant inter-species interaction and its effect on the position response function of cold atoms