Non-adiabatic non-linear impurities in linear hosts

We study the dynamics of non-adiabatic Holstein-type impurities embedded in an infinite linear chain. The impurities are modelled as Einstein oscillators coupled to specific sites of an infinite one-dimensional tight-binding host. We present numerical evidence providing bounds for the onset of self-trapping that depend critically on the initial conditions of the oscillators. We show that, in general, small but finite oscillator masses do not substantially change the self-trapped character of the states. For intermediate as well as large oscillator masses self-trapping can still occur for some initial oscillator preparations.