title: Topological order in the projected entangled-pair states formalism: transfer operator and boundary Hamiltonians.
abstract: We study the structure of topological phases and their boundaries in the projected entangled-pair states (PEPS) formalism. We show how topological order in a system can be identified from the structure of the PEPS transfer operator and subsequently use these findings to analyze the structure of the boundary Hamiltonian, acting on the bond variables, which reflects the entanglement properties of the system. We find that in a topological phase, the boundary Hamiltonian consists of two parts: A universal nonlocal part which encodes the nature of the topological phase and a nonuniversal part which is local and inherits the symmetries of the topological model, which helps to infer the structure of the boundary Hamiltonian and thus possibly of the physical edge modes.
authors.affiliation: Institut für Quanteninformation, RWTH Aachen, 52056 Aachen, Germany and Institute for Quantum Information, California Institute of Technology, MC 305-16, Pasadena, California 91125, USA.
authors.forename: Norbert
authors.initials: N
authors.lastname: Schuch
authors.forename: Didier
authors.initials: D
authors.lastname: Poilblanc
authors.forename: J Ignacio
authors.initials: JI
authors.lastname: Cirac
authors.forename: David
authors.initials: D
authors.lastname: Pérez-García