Laboratoire de Physique Théorique
Toulouse - UMR 5152

I will discuss the nature of the quantum phase transition out of charge-density-wave phase in the spinless fermion model with nearest- and next-nearest-neighbor interaction at one-third filling. Based on extensive Density Matrix Renormalization Group (DMRG) simulations I will show that the transition changes it nature from Kosterlitz-Thouless type for weak NNN interaction to the Pokrovsky-Talapov univerality class when NNN repulsion is strong. The latter describes a non-conformal commensurate-incommensurate transition and therefore it is accompanied by an appearance of a floating phase. Finally, I will argue that the change of the nature of the transition is a result of incommensurability induced by frustration and realized even at zero doping. The implications in the context of XXZ chain with next-nearest-neighbor Ising interaction will be briefly discussed.