The spin transport properties of a series of 3d transition metal(ii) phthalocyanines (MPc, M = Mn, Fe, Co, Ni, Cu and Zn) sandwiched between two semi-infinite armchair single-walled carbon nanotube electrodes are investigated by using a self-consistent ab initio approach that combines the non-equilibrium Green's function formalism with spin density functional theory. Our calculations show that ...

We investigate a lattice version of the Yang-Lee model which is characterized by a non-Hermitian quantum spin chain Hamiltonian. We propose a new way to implement PT -symmetry on the lattice, which serves to guarantee the reality of the spectrum in certain regions of values of the coupling constants. In that region of unbroken PT -symmetry we construct a Dyson map, a metric operator and find th...

We examine a periodic mixed spin chain with spin magnitudes 1 2 and 1 which are arrayed as 1 2 1 2 -1-1. The three independent parameters are ratios of the four exchange couplings. We determine phase boundaries in the parameter space by using the gapless condition which was previously derived by mapping a general inhomogeneous spin chain to the nonlinear σ model. We find two gapless boundaries ...

In the following we present an introduction to the mathematical theory of the XY spin chain. The importance of this model lies in the fact, first understood by Lieb, Schultz and Mattis in [4], that the XY spin chain is one of very few “exactly solvable” models in the theory of quantum many-body systems. Lieb, Schultz and Mattis considered the constant coefficient case. In the variable coefficie...

We apply a semiclassical approach to express finite temperature dynamical correlation functions of gapped spin models analytically. We show that the approach of [Á. Rapp, G. Zaránd, Phys. Rev. B 74, 014433 (2006)] can also be used for the S = 1 antiferromagnetic Heisenberg chain, whose lineshape can be measured experimentally. We generalize our calculations to O(N) quantum spin models and the s...

We report on the application of SPIN for model-checking C source code which is generated out of a textual domain-specific language (DSL). We have built a tool which automatically generates the necessary SPIN wrapper code using (meta-)information available at the DSL level. The approach is part of a larger tool-chain for developing mission critical applications. For example, error traces resulti...

We study the phase diagram of a quantum chain of spin-1/2 particles whose world lines form a dense loop gas with loop weight n. In addition to the usual two-site interaction corresponding to the XXZ spin chain, we introduce a three-site interaction. The resulting model contains a Majumdar-Ghosh-like gapped phase and a new integrable point, which we solve exactly. We also locate a critical line ...

Equation Basepoint Parameter Dimension Restrictions of Isotropy #1 W = XY + Z (0, 0, 0, 0) 4 #2 W 2 = XY + Z + 1 (1, 0, 0, 0) 3 #3 W = XY + Z +X (0, 0, 0, 0) 2 #4 W = XY + Z +XZ + αX (0, 0, 0, 0) α arbitrary 1 #5 W = XY + Z +XZ (0, 0, 0, 0) 1 #6 W 2 = XY +XY +XZ (1, 1, 0, 1) 1 #7 W = XY + Z (1, 0, 0, 1) α 6= 0, 1, 2 1 #8 W = XY + e (1, 0, 0, 0) 1 #9 W = XY + logZ (0, 0, 0, 1) 1 #10 W = XY + Z l...

Electron paramagnetic resonance (EPR) and differential scanning calorimetry (DSC) have been used to study the effect on the phase transition of dimyristoylphosphatidylcholine membranes of incorporating various stearic acid spin labels (SASL's) that contain the bulky oxazolidine ring at various positions along the stearyl chain. SASL's lowered the phase transition temperature and decreased the s...

The antiferromagnetic Heisenberg model on a chain with nearest and next nearest neighbor couplings is mapped onto the SO(3) nonlinear sigma model in the continuum limit. In one spatial dimension this model is always in its disordered phase and a gap opens to excited states. The latter form a doubly degenerate spin-1 branch at all orders in 1/N. We argue that this feature should be present in th...