Arnold Tongues and Feigenbaum Exponents of the Rational Mapping for Q-state Potts Model on Recursive Lattice: Q<2

We considered Q-state Potts model on Bethe lattice in presence of external magnetic field for Q<2 by means of recursion relation technique. This allows to study the phase transition mechanism in terms of the obtained one dimensional rational mapping. The convergence of Feigenabaum $\alpha$ and $\delta$ exponents for the aforementioned mapping is investigated for the period doubling and three cyclic window. We regarded the Lyapunov exponent as an order parameter for the characterization of the model and discussed its dependence on temperature and magnetic field. Arnold tongues analogs with winding numbers w=1/2, w=2/4 and w=1/3 (in the three cyclic window) are constructed for Q<2. The critical temperatures of the model are discussed and their dependence on Q is investigated. We also proposed an approximate method for constructing Arnold tongues via Feigenbaum $\delta$ exponent.Comment: 15 pages, 12 figure

Magnetic Properties and Thermal Entanglement on a Triangulated Kagome Lattice

The magnetic and entanglement thermal (equilibrium) properties in spin-1/2 Ising-Heisenberg model on a triangulated Kagome lattice are analyzed by means of variational mean-field like treatment based on Gibbs-Bogoliubov inequality. Because of the separable character of Ising-type exchange interactions between the Heisenberg trimers the calculation of quantum entanglement in a self-consistent field can be performed for each of the trimers individually. The concurrence in terms of three qubit isotropic Heisenberg model in effective Ising field is non-zero even in the absence of a magnetic field. The magnetic and entanglement properties exhibit common (plateau and peak) features observable via (antferromagnetic) coupling constant and external magnetic field. The critical temperature for the phase transition and threshold temperature for concurrence coincide in the case of antiferromagnetic coupling between qubits. The existence of entangled and disentangled phases in saturated and frustrated phases is established.Comment: 21 pages, 13 figure

Thermal Entanglement of a Spin-1/2 Ising-Heisenberg Model on a Symmetrical Diamond Chain

The entanglement quantum properties of a spin-1/2 Ising-Heisenberg model on a symmetrical diamond chain were analyzed. Due to the separable nature of the Ising-type exchange interactions between neighboring Heisenberg dimers, calculation of the entanglement can be performed exactly for each individual dimer. Pairwise thermal entanglement was studied in terms of the isotropic Ising-Heisenberg model, and analytical expressions for the concurrence (as a measure of bipartite entanglement) were obtained. The effects of external magnetic field $H$ and next-nearest neighbor interaction $J_m$ between nodal Ising sites were considered. The ground-state structure and entanglement properties of the system were studied in a wide range of the coupling constant values. Various regimes with different values of the ground-state entanglement were revealed, depending on the relation between competing interaction strengths. Finally, some novel effects, such as the two-peak behavior of concurrence versus temperature and coexistence of phases with different values of magnetic entanglement were observed

Azimuthal Dependence of the Heavy Quark Initiated Contributions to DIS

We analyze the azimuthal dependence of the heavy-quark-initiated contributions to the lepton-nucleon deep inelastic scattering (DIS). First we derive the relations between the parton level semi-inclusive structure functions and the helicity $\gamma^{*}Q$ cross sections in the case of arbitrary values of the heavy quark mass. Then the azimuth-dependent ${\cal O}(\alpha_{s})$ lepton-quark DIS is calculated in the helicity basis. Finally, we investigate numerically the properties of the $\cos\phi$ and $\cos2\phi$ distributions caused by the photon-quark scattering (QS) contribution. It turns out that, contrary to the basic photon-gluon fusion (GF) component, the QS mechanism is practically $\cos2\phi$-independent. This fact implies that measurements of the azimuthal distributions in charm leptoproduction could directly probe the charm density in the proton.Comment: 11 pages, 4 figures, revtex4, published versio

Thermal Entanglement and Critical Behavior of Magnetic Properties on a Triangulated Kagomé Lattice

The equilibrium magnetic and entanglement properties in a spin-1/2 Ising-Heisenberg model on a triangulated Kagomé lattice are analyzed by means of the effective field for the Gibbs-Bogoliubov inequality. The calculation is reduced to decoupled individual (clusters) trimers due to the separable character of the Ising-type exchange interactions between the Heisenberg trimers. The concurrence in terms of the three qubit isotropic Heisenberg model in the effective Ising field in the absence of a magnetic field is non-zero. The magnetic and entanglement properties exhibit common (plateau, peak) features driven by a magnetic field and (antiferromagnetic) exchange interaction. The (quantum) entangled and non-entangled phases can be exploited as a useful tool for signalling the quantum phase transitions and crossovers at finite temperatures. The critical temperature of order-disorder coincides with the threshold temperature of thermal entanglement

Phase transitions and entanglement properties in spin-1 Heisenberg clusters with single-ion anisotropy

The incipient quantum phase transitions of relevance to nonzero fluctuations and entanglement in Heisenberg clusters are studied in this paper by exploiting negativity as a measure in bipartite and frustrated spin-1 anisotropic Heisenberg clusters with bilinear-biquadratic exchange, single-ion anisotropy and magnetic field. Using the exact diagonalization technique, it is shown that quantum critical points signaled by qualitative changes in behavior of magnetization and particle number are ultimately related to microscopic entanglement and collective excitations. The plateaus and peaks in spin and particle susceptibilities define the conditions for a high/low-density quantum entanglement and various ordered phases with different spin (particle) concentrations

Deformation of orthosymplectic Lie superalgebra osp(1|2)

Triangular deformation of the orthosymplectic Lie superalgebra osp(1|4) is defined by chains of twists. Corresponding classical r-matrix is obtained by a contraction procedure from the trigonometric r-matrix. The carrier space of the constant r-matrix is the Borel subalgebra.Comment: LaTeX, 8 page