Density Matrix Spectra and Order Parameters in the 1D Extended Hubbard Model

Without any knowledge of the symmetry existing in the system, we derive the exact forms of the order parameters which show long-range correlation in the ground state of the one-dimensional extended Hubbard model using a quantum information approach. Our work demonstrates that the quantum information approach can help us to find the explicit form of the order parameter, which cannot be derived systematically via traditional methods in the condensed matter theory.