The Lambert-Tsallis Wq function

In the present work, we introduce the Lambert-Tsallis Wq function. It is a generalization of the Lambert W function, that solves the equation W-q(z)exq(W-q(z)) = z, where exp(q)(z) is the q-exponential used by Tsallis in nonextensive statistical mechanics. Here, we show some analytical results and its numerical calculation. We also introduce the disentropy, a function based on Wq that plays the opposite role of the entropy. At last, we use the disentropy for calculation of the disentanglement of two-qubit states. (C) 2019 Elsevier B.V. All rights reserved.