1205.1958 (Philipp Hauke)

Quantum disorder in the spatially completely anisotropic triangular
lattice II: frustrated hard-core bosons    [PDF]

Philipp Hauke

Spin liquids occuring in 2D frustrated spin systems were initially assumed to appear at strongest frustration, but evidence grows that they more likely intervene at transitions between two different types of order. To identify if this is more general, we here analyze a generalization of the spatially anisotropic triangular lattice (SATL) with antiferromagnetic XY interactions, the spatially \emph{completely} anisotropic triangular lattice (SCATL). This model can be implemented in experiments with trapped ions, ultra-small Josephson junctions, or ultracold atoms in optical lattices. Using Takahashi's modified spin-wave theory, complemented by exact diagonalizations, we find indications that indeed two different kinds of order are always separated by disordered phases. Our results further suggest that two gapped spin liquids, identified as distinct in the SATL, are actually continuously connected via the additional anisotropy of the SCATL. As these results indicate, this additional anisotropy -- allowing to approach spin liquid phases from different angles -- can give fundamental insight into the nature of quantum disordered phases.

View original: http://arxiv.org/abs/1205.1958