Kπ interaction in finite volume and the K* resonance

We evaluate energy levels of the $K\ensuremath{\pi}$ system in the ${K}^{*}$ channel in finite volume using chiral unitary theory. We use these energy levels to obtain $K\ensuremath{\pi}$ phase shifts and then obtain the ${K}^{*}$ mass and its decay width. We investigate their dependence on the pion mass and compare this with lattice QCD calculations. We also compare our method with the standard L\"uscher approach and solve the inverse problem to obtain the $K\ensuremath{\pi}$ phase shifts from these ``synthetic'' lattice data.