STRONG-COUPLING SYSTEM OF THE ELECTRON-RIPPLON ON LIQUID-HELIUM FILM

The Landau-Pekar variational theory for investigating the strong-coupling system of electron-phonon in crystals is employed to study the system of an electron strongly coupled to ripplons on the outer surface of the liquid-helium film. Analytical expressions of the ground state energy, the effective mass, the average number of virtual ripplons around the electron and the spatial extension of the electron are obtained. A dimensionless quantity of effective mass ratio has been introduced and compared with the model mass and the Feynman mass which exist in the literature.