Photosolitonic effect

We show that dark solitons in one-dimensional Bose liquids may be created by absorption of a single quanta of an external ac field, in a close analogy with the Einstein's photoelectric effect. Similarly to the von Lenard's experiment with photoexcited electrons, the external field's photon energy □ω should exceed a certain threshold. In our case the latter is given by the soliton energy εs (□q) with the momentum □q, where q is photon's wave number. We find the probability of soliton creation to have a power-law dependence on the frequency detuning ω- εs ?□. This dependence is a signature of the quantum nature of the absorption process and the orthogonality catastrophe phenomenon associated with it.