3,954 research outputs found
Ground state energy and mass gap of a generalised quantum spin ladder
We show that a 2-leg ladder hamiltonian introduced recently by Albeverio and
Fei (cond-mat/9807341) can be made to satisfy the Hecke algebra. As a result we
have found an equivalent representation of the eigenspectrum in terms of the
spin-1/2 antiferromagnetic XXZ chain at . The values of
thermodynamic quantities such as the ground state energy and mass gap follow
from the known XXZ results.Comment: 8 pages, Late
Exactly solvable quantum spin tubes and ladders
We find families of integrable n-leg spin-1/2 ladders and tubes with general
isotropic exchange interactions between spins. These models are equivalent to
su(N) spin chains with N=2^n. Arbitrary rung interactions in the spin tubes and
ladders induce chemical potentials in the equivalent spin chains. The
potentials are n-dependent and differ for the tube and ladder models. The
models are solvable by means of nested Bethe Ansatz.Comment: 6 pages, Latex, 1 eps fig, to appear in J. Phys.
Excitations in the dilute A_L lattice model: E_6, E_7 and E_8 mass spectra
On the basis of features observed in the exact perturbation approach solution
for the eigenspectrum of the dilute A_3 model, we propose expressions for
excitations in the dilute A_4 and A_6 models. Principally, we require that
these expressions satisfy the appropriate inversion relations. We demonstrate
that they give the expected E_7 and E_6 mass spectra, and universal amplitudes,
and agree with numerical expressions for the eigenvalues.Comment: 16 pages, Latex, Elsevier style file
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