It is observed that when the conformational properties of DNA molecule are mapped onto an antiferromagnetic spin system we can realize the specific properties of the rod-like-chain (RLC) model where the analytically continued partition function corresponds to the symmetric top Hamiltonian. The relevant path integral represents a charge particle in the field of a non-quantized monopole which sug...

We analyze the fast-moving string in the magnetic Melvin field background and find that the associated effective Lagrangian of string sigma model describes the spin chain model with external magnetic field. The spin vector in the spin chain has been properly deformed and is living on the deformed two-sphere or deformed two-dimensional hyperboloid, depending on the direction around which the str...

We investigate the ground-state property of an eg-orbital Hubbard model at quarter filling on a zigzag chain by exploiting the density matrix renormalization group method. When two orbitals are degenerate, the zigzag chain is decoupled to a doble-chain spin system to suppress the spin frustration due to the spatial anisotropy of the occupied orbital. On the other hand, when the level splitting ...

We construct the family of spin chain Hamiltonians, which have affine quantum group symmetry U q ˆ g. Their eigenvalues coincide with the eigen-values of the usual spin chain Hamiltonians, but have the degeneracy of levels, corresponding to affine U q ˆ g. The space of states of these spin chains is formed by the tensor product of fully reducible representations of quantum group. The fermionic ...