M. Kaulke et I. Peschel, A DMRG STUDY OF THE Q-SYMMETRICAL HEISENBERG CHAIN, The European Physical Journal. B: Condensed Matter Physics, 5(3), 1998, pp. 727-734
The spin one-half Heisenberg chain with U-q[SU(2)] symmetry is studied
via density-matrix renormalization. Ground-state energy and q-symmetr
ic correlation functions are calculated for the non-Hermitian case q =
exp(i pi(r+1)) with integer r. This gives bulk and surface exponents
for (para)fermionic correlations in the related Ising and Potts models
. The case of real q corresponding to a diffusion problem is treated a
nalytically.