Quantum phase transitions in the dimerized extended BoseHubbard model
Abstract
We present an unbiased numerical densitymatrix renormalization group study of the onedimensional BoseHubbard model supplemented by nearestneighbor Coulomb interaction and bond dimerization. It places the emphasis on the determination of the groundstate phase diagram and shows that, besides dimerized Mott and densitywave insulating phases, an intermediate symmetryprotected topological Haldane insulator emerges at weak Coulomb interactions for filling factor one, which disappears, however, when the dimerization becomes too large. Analyzing the critical behavior of the model, we prove that the phase boundaries of the Haldane phase to Mott insulator and densitywave states belong to the Gaussian and Ising universality classes with central charges $c=1$ and $c=1/2$, respectively, and merge in a tricritical point. Interestingly we can demonstrate a direct Ising quantum phase transition between the dimerized Mott and densitywave phases above the tricritical point. The corresponding transition line terminates at a critical end point that belongs to the universality class of the dilute Ising model with $c=7/10$. At even stronger Coulomb interactions the transition becomes first order.
 Publication:

arXiv eprints
 Pub Date:
 December 2018
 DOI:
 10.48550/arXiv.1812.03489
 arXiv:
 arXiv:1812.03489
 Bibcode:
 2018arXiv181203489S
 Keywords:

 Condensed Matter  Quantum Gases;
 Condensed Matter  Strongly Correlated Electrons
 EPrint:
 7 pages, 6 figures