title: Boundary-locality and perturbative structure of entanglement spectra in gapped systems.
abstract: The entanglement between two parts of a many-body system can be characterized in detail by the entanglement spectrum. Focusing on gapped phases of several one-dimensional systems, we show how this spectrum is dominated by contributions from the boundary between the parts. This contradicts the view of an "entanglement Hamiltonian" as a bulk entity. The boundary-local nature of the entanglement spectrum is clarified through its hierarchical level structure, through the combination of two single-boundary spectra to form a two-boundary spectrum, and finally through consideration of dominant eigenfunctions of the entanglement Hamiltonian. We show consequences of boundary-locality for perturbative calculations of the entanglement spectrum.
authors.affiliation: Max-Planck-Institut für Physik komplexer Systeme, Nöthnitzer Straße 38, D-01187 Dresden, Germany.
authors.forename: Vincenzo
authors.initials: V
authors.lastname: Alba
authors.forename: Masudul
authors.initials: M
authors.lastname: Haque
authors.forename: Andreas M
authors.initials: AM
authors.lastname: Läuchli