Static and Dynamic Properties of Antiferromagnetic Heisenberg Ladders: Fermionic versus Bosonic Approaches

Abstract

In terms of spinless fermions via the Jordan–Wigner transformation along a snakelike path and spin waves modified so as to restore the sublattice symmetry, we investigate the static and dynamic properties of two-leg antiferromagnetic Heisenberg ladders. The specific heat is finely reproduced by the spinless fermions, whereas the magnetic susceptibility is well described by the modified spin waves. The nuclear spin–lattice relaxation rate is discussed in detail with particular emphasis on its novel field dependence.