FORM-FACTORS COMPUTATION OF FRIEDEL OSCILLATIONS IN LUTTINGER LIQUIDS

We show how the form-factors approach can be used to compute correlato rs of operators with non-trivial anomalous dimension in quantum impuri ty problems. This is done by a series of regularizations that cure com pletely the infrared, divergencies, without spoiling the exactedness o f the method. As an application, we compute for g less than or equal t o 1/2 the 'Friedel oscillations' of charge density induced by a single impurity in a one-dimensional Luttinger liquid of spinless electrons.