Regensburg 2019 – scientific programme
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TT: Fachverband Tiefe Temperaturen
TT 30: Correlated Electrons: 1D Theory
TT 30.8: Talk
Tuesday, April 2, 2019, 15:45–16:00, H4
Rhombi-chain Bose-Hubbard model: Geometric frustration and interactions — Christine Cartwright1, Gabriele De Chiara1, and •Matteo Rizzi2 — 1Centre for Theoretical Atomic, Molecular and Optical Physics, Queen’s University Belfast, Belfast BT7 1NN, United Kingdom — 2Institut für Physik, Johannes Gutenberg Universität, Staudingerweg 7, 55099 Mainz, Germany
We explore the effects of geometric frustration within a one-dimensional Bose-Hubbard model using a chain of rhombi subject to a magnetic flux. The competition of tunneling, self-interaction, and magnetic flux gives rise to the emergence of a pair-superfluid (pair-Luttinger liquid) phase besides the more conventional Mott-insulator and superfluid (Luttinger liquid) phases. We compute the complete phase diagram of the model by identifying characteristic properties of the pair-Luttinger liquid phase such as pair correlation functions and structure factors and find that the pair-Luttinger liquid phase is very sensitive to changes away from perfect frustration (half-flux). We provide some proposals to make the model more resilient to variants away from perfect frustration. We also study the bipartite entanglement properties of the chain. We discover that, while the scaling of the block entropy pair-superfluid and of the single-particle superfluid leads to the same central charge, the properties of the low-lying entanglement spectrum levels reveal their fundamental difference.
Phys. Rev. B 98, 184508 (2018)