We consider a quasi-one-dimensional system of spin-1 Heisenberg antiferromagnetic chains in two-dimensional and three-dimensional hypercubic lattices with interchain coupling J and uniaxial single-ion anisotropy D. Using large-scale numerical simulations, we map out the J-D phase diagram and investigate the low-lying excitations of the Haldane phase in the J≪1 limit. We also provide direct evid...

We show that the SU(N), level-1 Wess-Zumino-Witten conformal field theory provides a natural realization of the Yangian Y(sl~) for N _> 3. We also construct a hamiltonian/-/2 which commutes with the Yangian generators and study its spectrum. Our results, which generalize work by Haldane et al. [ 1 ], provide the field theory extension of the algebraic structure of the SU(N) Haldane-Shastry spin...

The hierarchy of Integrable Spin Chain Hamiltonians, which are trigonometric analogs of the Haldane Shastry Model and the associated higher conserved charges, is derived by a reduction from the trigonometric Dynamical Models of Bernard-Gaudin-Haldane-Pasquier. The Spin Chain Hamiltonians have the property of U ′ q(ĝl2)-invariance. The spectrum of the Hamiltonians and the U ′ q(ĝl2)-representati...

Following the Haldane conjecture, the antiferromagnetic (AF) Heisenberg chain of integer spins has a singlet ground state separated from the excited states by an energy gap. Recent numerical calculations on finite AF chains with S = 1 supported this conjecture and provided an approximate value for the energy gap: EG "",0.41 J I, where J is the intrachain exchange interaction. We report experime...

Ground-state of the S = 1 XXZ spin chain under the influence of the random magnetic field is studied by means of the exactdiagonalization method. The S = 1/2 counterpart has been investigated extensively so far. The easy-plane area, including the Haldane and the XY phases, is considered. The area suffers significantly from the magnitude of the constituent spin. Destruction of the Haldane state ...

In an earlier paper[1] I showed that the Contractor Renormalization group (CORE) method could be used to map a theory of free quarks, and quarks interacting with gluons, into a generalized frustrated Heisenberg antiferromagnet (HAF) and proposed using CORE methods to study these theories. Since generalizations of HAF’s exhibit all sorts of subtle behavior which, from a continuum point of view, ...

Results of magnetization and high-field electron spin resonance (ESR) studies of the new spin-1 Haldane-chain material [Ni(C2H8N2)2NO2] (BF4) (NENB) are reported. A definite signature of the Haldane state in NENB was obtained. From the analysis of the frequency–field dependence of magnetic excitations in NENB, the spin-Hamiltonian parameters were calculated, yielding 1/kB = 17.4 K, g‖ = 2.14, D...

The wave functions of the Haldane-Rezayi paired Hall state have been previously described by a non-unitary conformal eld theory with central charge c = ?2. Moreover, a relation with the c = 1 unitary Weyl fermion has been suggested. We construct the complete unitary theory and show that it consistently describes the edge excitations of the Haldane-Rezayi state. Actually, we show that the unitar...