Rostock 2019 – wissenschaftliches Programm

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Q: Fachverband Quantenoptik und Photonik

Q 25: Poster: Quantum Optics and Photonics I

Q 25.8: Poster

Dienstag, 12. März 2019, 16:30–18:30, S Atrium Informatik

Quench dynamics and boundary condition dependence of the one-dimensional extended Bose Hubbard model — •Sebastian Stumper, Junichi Okamoto, and Michael Thoss — Insitute of Physics, University of Freiburg, Freiburg, Germany

The one-dimensional extended Bose Hubbard model exhibits a variety of quantum phases due to its competing interactions. For large on-site interactions, a Mott insulating (MI) phase exists, while a charge density wave (CDW) phase becomes dominant for large nearest-neighbour interactions. In between these phases, there exists a topologically non-trivial phase of a Haldane insulator (HI), which is characterized by a non-local string order (Phys. Rev. Lett. 97, 260401 (2006)). Ground state properties and low energy spectra are, however, very sensitive to the treatment of boundary conditions (arXiv:1403.2315 (2014)). We study an open chain of the extended Bose Hubbard model for various configurations of chemical potentials applied at the edges using the density matrix renormalization group method (Comput. Phys. Commun. 225, 59 (2018)). Without edge potentials, the CDW and HI phases show a non-degenerate ground state, and the order parameters change signs in the middle of the chain. This feature is robust against finite size scaling and is explained by a simple effective picture for the low energy states. On the other hand, with large edge potentials, the sign change of the order parameters disappears, and we recover uniform bulk ground states. Furthermore, we simulate quenched dynamics with initial states from MI, HI and CDW phases and discuss the results in terms of our findings on the equilibrium cases.