title: Eigenstate thermalization in the two-dimensional transverse field Ising model.
abstract: We study the onset of eigenstate thermalization in the two-dimensional transverse field Ising model (2D-TFIM) in the square lattice. We consider two nonequivalent Hamiltonians: the ferromagnetic 2D-TFIM and the antiferromagnetic 2D-TFIM in the presence of a uniform longitudinal field. We use full exact diagonalization to examine the behavior of quantum chaos indicators and of the diagonal matrix elements of operators of interest in the eigenstates of the Hamiltonian. An analysis of finite size effects reveals that quantum chaos and eigenstate thermalization occur in those systems whenever the fields are nonvanishing and not too large.
authors.affiliation: Department of Physics, Pennsylvania State University, University Park, Pennsylvania 16802, USA.|Beijing Computational Science Research Center, Beijing 100193, China.
authors.forename: Rubem
authors.initials: R
authors.lastname: Mondaini
authors.affiliation: Department of Physics, University of California, Santa Barbara, California, 93106, USA.
authors.forename: Keith R
authors.initials: KR
authors.lastname: Fratus
authors.affiliation: Department of Physics, University of California, Santa Barbara, California, 93106, USA.
authors.forename: Mark
authors.initials: M
authors.lastname: Srednicki
authors.affiliation: Department of Physics, Pennsylvania State University, University Park, Pennsylvania 16802, USA.
authors.forename: Marcos
authors.initials: M
authors.lastname: Rigol