title: Entanglement convertibility by sweeping through the quantum phases of the alternating bonds XXZ chain.
abstract: We study the entanglement structure and the topological edge states of the ground state of the spin-1/2 XXZ model with bond alternation. We employ parity-density matrix renormalization group with periodic boundary conditions. The finite-size scaling of Rényi entropies S2 and S∞ are used to construct the phase diagram of the system. The phase diagram displays three possible phases: Haldane type (an example of symmetry protected topological ordered phases), Classical Dimer and Néel phases, the latter bounded by two continuous quantum phase transitions. The entanglement and non-locality in the ground state are studied and quantified by the entanglement convertibility. We found that, at small spatial scales, the ground state is not convertible within the topological Haldane dimer phase. The phenomenology we observe can be described in terms of correlations between edge states. We found that the entanglement spectrum also exhibits a distinctive response in the topological phase: the effective rank of the reduced density matrix displays a specifically large "susceptibility" in the topological phase. These findings support the idea that although the topological order in the ground state cannot be detected by local inspection, the ground state response at local scale can tell the topological phases apart from the non-topological phases.
authors.affiliation: Department of Physics, National Chung Hsing University, Taichung 40227, Taiwan.|Center of Theoretical Sciences, National Taiwan University, Taipei 10617, Taiwan.
authors.forename: Yu-Chin
authors.initials: YC
authors.lastname: Tzeng
authors.affiliation: Department of Physics, National Chung Hsing University, Taichung 40227, Taiwan.
authors.forename: Li
authors.initials: L
authors.lastname: Dai
authors.affiliation: Department of Physics, National Chung Hsing University, Taichung 40227, Taiwan.
authors.forename: Ming-Chiang
authors.initials: MC
authors.lastname: Chung
authors.affiliation: CNR-MATIS-IMM &Dipartimento di Fisica e Astronomia, Universitá di Catania, &INFN-Laboratori Nazionali del Sud, Via S. Sofia 64, 95127 Catania (Italy).|Centre for Quantum Technologies, National University of Singapore, 3 Science Drive 2, Singapore 117543, Singapore.
authors.forename: Luigi
authors.initials: L
authors.lastname: Amico
authors.affiliation: Centre for Quantum Technologies, National University of Singapore, 3 Science Drive 2, Singapore 117543, Singapore.|Institute of Advanced Studies, Nanyang Technological University, 60 Nanyang View, Singapore 639673, Singapore.|National Institute of Education, Nanyang Technological University, 1 Nanyang Walk, Singapore 637616, Singapore.|MajuLab, CNRS-UNS-NUS-NTU International Joint Research Unit, UMI 3654, Singapore.
authors.forename: Leong-Chuan
authors.initials: LC
authors.lastname: Kwek