  Brownian motion of colloidal particles in the quasi-two-dimensional (qTD)
confinement displays distinct kinetic characters from that in bulk. Here we
experimentally report a dynamic evolution of Brownian particles in the qTD
system. The dynamic system displays a quasi-equilibrium state of colloidal
particles performing Brownian motion. In the quasi-equilibrium process, the qTD
confinement results in the coupling of particle motions, which slowly dampens
the motion and interaction of particles until the final equilibrium state
reaches. The theory is developed to explain coupling motions of Brownian
particles in the qTD confinement.
