Electronic momentum distribution in the one-dimensional extended Hubbard model: determinantal Monte Carlo study

The effect of electron–electron (e–e) interaction on trans-polyacetylene (t-PA) properties is investigated within the framework of an extended Hubbard model in one dimension. For numerical calculation, we use the determinantal version of quantum Monte Carlo approach, which provides a breakthrough to simulate statistical fluctuations in the systems with many degrees of freedom, in order to obtain mean values for observables of physical interest. This allows one to analyze the discrete system of fermions without encountering the numerical instabilities that generally occur from the original problem involving anticommuting fermion operators. We calculate the electronic momentum distribution function n(k) for on-site interaction U and nearest-neighbor interaction E, where U<4t, U≃4t and U>4t, with E∈[U/2,U], (t is the hopping matrix elements).