Volume 94, Number 1, April 2011
|Number of page(s)
|Condensed Matter: Electronic Structure, Electrical, Magnetic and Optical Properties
|05 April 2011
Effective models for gapped phases of strongly correlated quantum lattice models
Lehrstuhl für Theoretische Physik I, TU Dortmund - Otto-Hahn-Straß e 4, D-44221 Dortmund, Germany, EU
Accepted: 7 March 2011
We present a robust scheme to derive effective models non-perturbatively for quantum lattice models when at least one degree of freedom is gapped. A combination of graph theory and the method of continuous unitary transformations (gCUTs) is shown to efficiently capture all zero-temperature fluctuations in a controlled spatial range. The gCUT can be used either for effective quasi-particle descriptions or for effective low-energy descriptions in case of infinitely degenerate subspaces. We illustrate the method for 1d and 2d lattice models yielding convincing results in the thermodynamic limit. We find that the recently discovered spin liquid in the Hubbard model on the honeycomb lattice lies outside the perturbative strong-coupling regime. Various extensions and perspectives of the gCUT are discussed.
PACS: 71.27.+a – Strongly correlated electron systems; heavy fermions / 75.10.Jm – Quantized spin models, including quantum spin frustration / 05.30.Pr – Fractional statistics systems (anyons, etc.)
© EPLA, 2011
Current usage metrics show cumulative count of Article Views (full-text article views including HTML views, PDF and ePub downloads, according to the available data) and Abstracts Views on Vision4Press platform.
Data correspond to usage on the plateform after 2015. The current usage metrics is available 48-96 hours after online publication and is updated daily on week days.
Initial download of the metrics may take a while.