Phase diagram of the Heisenberg spin ladder with ring exchange

Magnetic Phase Diagram of Spin-1/2 Two-Leg Ladder with Four-Spin Ring Exchange

We study the spin-1/2 two-leg Heisenberg ladder with four-spin ring exchanges under a magnetic field. We introduce an exact duality transformation which is an extension of the spin-chirality duality developed previously and yields a new self-dual surface in the parameter space. We then determine the magnetic phase diagram using the numerical approaches of the density-matrix renormalization-grou...

The phase diagram of the anisotropic Spin-1 Heisenberg Chain

Quantum Phase Diagram of an Exactly Solved Mixed Spin Ladder

We investigate the quantum phase diagram of the exactly solved mixed spin-(1 2 , 1) ladder via the thermodynamic Bethe ansatz (TBA). In the absence of a magnetic field the model exhibits three quantum phases associated with su(2), su(4) and su(6) symmetries. In the presence of a strong magnetic field, there is a third and full saturation magnetization plateaux within the strong antiferromagneti...

Phase Diagram of the Spin-One Heisenberg System with Dimerization and Frustration

We use the density matrix renormalization group method to study the ground state properties of an antiferromagnetic spin-1 chain with a next-nearest neighbor exchange J2 and an alternation δ of the nearest neighbor exchanges. We find a line running from a gapless point at (J2, δ) = (0, 0.25 ± 0.01) upto an almost gapless point at (0.725 ± 0.01, 0 such that the open chain ground state is 4-fold ...

Quantum Entanglement in the S=1/2 Spin Ladder with Ring Exchange

In this paper we study the concurrence and the block-block entanglement in the S = 1/2 spin ladder with four-spin ring exchange by the exact diagonalization method of finite cluster of spins. The relationship between the global phase diagram and the ground-state entanglement is investigated. It is shown that the block-block entanglement of different block size and geometry manifests richer info...