Integrable isotropic chains with arbitrary spin

A. G. Antipov, Igor V. Komarov

H. Babujian

Horaƫiu Năstase

Andreas Klümper, Dominic Nawrath, Junji Suzuki

We derive algebraic formulae for the density matrices of finite segments of the integrable s u (2) isotropic spin-1 chain in the thermodynamic limit. We give explicit results for the 2- and 3-site cases for arbitrary temperature T and zero field. In the zero-temperature limit the correlation functions are given in elementary form in terms of Riemann's zeta function at even integer arguments.

Jens Damerau, Frank Göhmann, Nils P Hasenclever +1 more

We derive a multiple integral representing the ground-state density matrix of a segment of length m of the XXZ spin chain on L lattice sites, which depends on L only parametrically. This allows us to treat chains of arbitrary finite length. Specializing to the isotropic limit of the XXX chain we show for small m that the multiple integrals factorize. We conjecture that this property holds for arbitrary m and suggest an exponential formula for the density matrix which involves only a double Cauchy type integral in the exponent. We demonstrate the efficiency of our formula by computing the next-to-nearest neighbour zz -correlation function for chain lengths ranging from two to macroscopic numbers.

P. P. Kulish