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

Production of scalar KKˉK\bar K molecules in ϕ\phi radiative decays

The potentialities of the production of the scalar $K\bar K$ molecules in the $\phi$ radiative decays are considered beyond the narrow resonance width approximation. It is shown that $BR(\phi\rightarrow\gamma f_0(a_0)\rightarrow\gamma\pi\pi(\pi\eta))\approx (1\div 2)\times 10^{-5}\ ,\BR(\phi\rightarrow\gamma (f_0+a_0)\rightarrow\gamma K^+K^-)\alt 10^{-6}$and$BR(\phi\rightarrow\gamma (f_0+a_0) \to \gamma K^0\bar K^0)\alt 10^{-8}$. The mass spectra in the$\pi\pi\ ,\ \pi\eta\ ,\ K^+K^-\ ,\ K^0\bar K^0$channels are calculated. The imaginary part of the amplitude$\phi\rightarrow\gamma f_0(a_0)$is calculated analytically. It is obtained the phase of the scalar resonance production amplitude that causes the interference patterns in the reaction$e^+e^-\rightarrow\gamma \pi^+\pi^-$in the$\phi$ meson mass region.Comment: 19 pages, revtex, 4 eps files of figure

The Effect of Type Ibc Contamination in Cosmological Supernova Samples

We explore the effect of contamination of intermediate redshift Type Ia supernova samples by Type Ibc supernovae. Simulating observed samples of Ia and mixed Ibc/Ia populations at a range of redshifts for an underlying cosmological concordance model (\Omega_{m}=0.27, \Omega_{\Lambda}=0.73), we find that even small contamination levels, 2-5% may bias the derived \Omega_{\Lambda} and \Omega_{m} towards larger values. We thus emphasize the need for clean samples of Type Ia SNe for accurate measurements of the cosmological parameters. We also simulate a SN sample similar to the fiducial SNAP detected distribution (Kim et al. 2004), but include Ibc contamination. For this distribution we illustrate the effect of Ibc contamination on the distance modulus vs. redshift diagram for low and high precision measurements.Comment: ApJ accepte

Symmetries of Three Harmonically-Trapped Particles in One Dimension

We present a method for solving trapped few-body problems and apply it to three equal-mass particles in a one-dimensional harmonic trap, interacting via a contact potential. By expressing the relative Hamiltonian in Jacobi cylindrical coordinates, i.e. the two-dimensional version of three-body hyperspherical coordinates, we discover an underlying ${\rm C}_{6v}$ symmetry. This symmetry simplifies the calculation of energy eigenstates of the full Hamiltonian in a truncated Hilbert space constructed from the trap Hamiltonian eigenstates. Particle superselection rules are implemented by choosing the relevant representations of ${\rm C}_{6v}$. We find that the one-dimensional system shows nearly the full richness of the three-dimensional system, and can be used to understand separability and reducibility in this system and in standard few-body approximation techniques.Comment: 27 pages, 5 figures, 6 tables, 37 references, 4 footnotes, 1 article; v2 has revised introduction and results sections as well as typos correcte