Quantum phase transition and von Neumann entropy of quasiperiodic Hubbard chains

The half-filled Hubbard chains with the Fibonacci and Harpermodulating site potentials are studied in a self-consistentmean-field approximation. A new order parameter is introduced todescribe a charge density order. We also calculate the von Neumannentropy of the ground state. The results show that the von Neumannentropy can identify a CDW/SDW (charge density wave/spin densitywave) transition for quasiperiodic models.