title: Critical behavior of a quantum chain with four-spin interactions in the presence of longitudinal and transverse magnetic fields.
abstract: We study the ground-state properties of a spin-1/2 model on a chain containing four-spin Ising-like interactions in the presence of both transverse and longitudinal magnetic fields. We use entanglement entropy and finite-size scaling methods to obtain the phase diagrams of the model. Our numerical calculations reveal a rich variety of phases and the existence of multicritical points in the system. We identify phases with both ferromagnetic and antiferromagnetic orderings. We also find periodically modulated orderings formed by a cluster of like spins followed by another cluster of opposite like spins. The quantum phases in the model are found to be separated by either first- or second-order transition lines.
authors.affiliation: Departamento de Física, Universidade Federal Fluminense, Avenida Litorânea s/n, Niterói 24210-340, RJ, Brazil.
authors.forename: B
authors.initials: B
authors.lastname: Boechat
authors.affiliation: Departamento de Física, Universidade Federal Fluminense, Avenida Litorânea s/n, Niterói 24210-340, RJ, Brazil.
authors.forename: J
authors.initials: J
authors.lastname: Florencio
authors.affiliation: Departamento de Física, Universidade Federal Fluminense, Avenida Litorânea s/n, Niterói 24210-340, RJ, Brazil.
authors.forename: A
authors.initials: A
authors.lastname: Saguia
authors.affiliation: Department of Physics, University of Portland, Portland, Oregon 97203, USA.
authors.forename: O F
authors.initials: OF
authors.lastname: de Alcantara Bonfim