Illustration from Scientific Research

Schematic representation of the experiment. A charged dielectric microparticle dispersed in water is confined in a parabolic trap generated by a tightly focused infrared laser. Its effective temperature is controlled by an electric field that shakes the particle, mimicking a thermal bath at a higher temperature than the water. An arbitrary signal generator feeds a noisy signal with a white Gaussian spectrum into a pair of gold microelectrodes immersed in the liquid, thus producing the required electric field. Therefore, the particle exhibits Brownian motion inside the trap. This motion has a Gaussian distribution whose variance is determined by the effective temperature.

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