Entanglement and ground state level crossings in an extended Hubbard dimer


Proceedings of the 34th Samahang Pisika ng Pilipinas Physics Congress, University of the Philippines Visayas, Iloilo City, 18–21 Aug 2016, SPP-2016-PB-20.


The single-site entanglement entropy in the ground state of an extended Hubbard dimer is calculated in terms of intrasite and intersite interaction parameters. Entanglement vanishes in a ferromagnetic regime characterized by a degenerate spin-polarized ground state. In parameter ranges with non-zero entanglement, the ground state is a linear combination of states with spin and charge modulation.