Baxter Operators and Hamiltonians for "nearly all" Integrable Closed   gl(n) Spin Chains
  We continue our systematic construction of Baxter Q-operators for spin chains, which is based on certain degenerate solutions of the Yang-Baxter equation. Here we generalize our approach from the fundamental representation of gl(n) to generic finite-dimensional representations in quantum space. The results equally apply to non-compact representations of highest or lowest weight type. We furthermore fill an apparent gap in the literature, and provide the nearest-neighbor Hamiltonians of the spin chains in question for all cases where the gl(n) representations are described by rectangular Young diagrams, as well as for their infinite-dimensional generalizations. They take the form of digamma functions depending on operator-valued shifted weights. 
Rouven Frassek, Tomasz Lukowski, Carlo Meneghelli, Matthias Staudacher
math-ph hep-th math.MP