Coherent responses of resonance atom layer to short optical pulse excitation

Coherent responses of resonance atom layer to short optical pulse excitation are numerically considered. The inhomogeneous broadening of one-photon transition, the local field effect, and the substrate dispersion are involved into analysis. For a certain intensity of incident pulses a strong coherent interaction in the form of sharp spikes of superradiation is observed in transmitted radiation. The Lorentz field correction and the substrate dispersion weaken the effect, providing additional spectral shifts. Specific features of photon echo in the form of multiple responses to a double or triple pulse excitation is discussed.Comment: only PDF,15 page

Phase Structure of the Interacting Vector Boson Model

The two-fluid Interacting Vector Boson Model (IVBM) with the U(6) as a dynamical group possesses a rich algebraic structure of physical interesting subgroups that define its distinct exactly solvable dynamical limits. The classical images corresponding to different dynamical symmetries are obtained by means of the coherent state method. The phase structure of the IVBM is investigated and the following basic phase shapes, connected to a specific geometric configurations of the ground state, are determined: spherical, $U_{p}(3)\otimes U_{n}(3)$, $\gamma-$unstable, O(6), and axially deformed shape, $SU(3)\otimes U_{T}(2)$. The ground state quantum phase transitions between different phase shapes, corresponding to the different dynamical symmetries and mixed symmetry case, are investigated.Comment: 9 pages, 10 figure

The general harmonic-oscillator brackets: compact expression, symmetries, sums and Fortran code

We present a very simple expression and a Fortran code for the fast and precise calculation of three-dimensional harmonic-oscillator transformation brackets. The complete system of symmetries for the brackets along with analytical expressions for sums, containing products of two and three brackets, is given.Comment: 13 pages, accepted for publication in Nuclear Physics

Ground-gamma band mixing and evolution of collectivity in even-even neutron-rich nuclei with 40<Z<50

We propose an extended band mixing formalism capable of describing the ground-gamma band interaction in a wide range of collective spectra beyond the regions of well deformed nuclei. On this basis we explain the staggering effects observed in the gamma bands of Mo, Ru and Pd nuclei providing a consistent interpretation of new experimental data in the neutron rich region. As a result the systematic behavior of the odd-even staggering effect and some general characteristics of the spectrum such as the mutual disposition of the bands, the interaction strength and the band structures is explained as the manifestation of respective changes in collective dynamics of the system.Comment: 17 pages, 6 figures, 4 table

Energy Systematics of Low-lying Collective States within the Framework of the Interacting Vector Boson Model

In a new application of the algebraic Interacting Vector Boson Model (IVBM), we exploit the reduction of its Sp(12,R) dynamical symmetry group to Sp(4,R) x SO(3), which defines basis states with fixed values of the angular momentum L. The relationship of the latter to $U(6) \subset U(3)x U(2), which is the rotational limit of the model, means the energy distribution of collective states with fixed angular momentum can be studied. Results for low-lying spectra of rare-earth nuclei show that the energies of collective positive parity states with L=0,2,4,6... lie on second order curves with respect to the number of collective phonons n or vector bosons N=4n out of which the states are built. The analysis of this behavior leads to insight regarding the common nature of collective states, tracking vibrational as well as rotational features.Comment: 8 pages, 5 figures, 4 table

Nonlinear response of a thin metamaterial film containing Josephson junctions

An interaction of electromagnetic field with metamaterial thin film containing split-ring resonators with Josephson junctions is considered. It is shown that dynamical self-inductance in a split rings results in reduction of magnetic flux through a ring and this reduction is proportional to a time derivative of split ring magnetization. Evolution of thin film magnetization taking into account dynamical self-inductance is studied. New mechanism for excitation of waves in one dimensional array of split-ring resonators with Josephson junctions is proposed. Nonlinear magnetic susceptibility of such thin films is obtained in the weak amplitude approximation.Comment: 6 figure

Six-dimensional Davidson potential as a dynamical symmetry of the symplectic Interacting Vector Boson Model

A six-dimensional Davidson potential, introduced within the framework of the Interacting Vector Boson Model (IVBM), is used to describe nuclei that exhibit transitional spectra between the purely rotational and vibrational limits of the theory. The results are shown to relate to a new dynamical symmetry that starts with the $Sp(12,R) \supset SU(1,1) \times SO(6)$ reduction. Exact solutions for the eigenstates of the model Hamiltonian in the basis defined by a convenient subgroup chain of SO(6) are obtained. A comparison of the theoretical results with experimental data for heavy nuclei with transitional spectra illustrates the applicability of the theory.Comment: 9 pages, 4 figure

Canonical histone H2Ba and H2A.X dimerize in an opposite genomic localization to H2A.Z/H2B.Z dimers in Toxoplasma gondii

Histone H2Ba of Toxoplasma gondii was expressed as recombinant protein (rH2Ba) and used to generate antibody in mouse that is highly specific. Antibody recognizing rH2Ba detects a single band in tachyzoite lysate of the expected molecular weight (12kDa). By indirect immunofluorescence (IFA) in in vitro grown tachyzoites and bradyzoites, the signal was detected only in the parasite nucleus. The nucleosome composition of H2Ba was determined through co-immunoprecipitation assays. H2Ba was detected in the same immunocomplex as H2A.X, but not with H2A.Z. Through chromatin immunoprecipitation (ChIP) assays and qPCR, it was observed that H2Ba is preferentially located at promoters of inactive genes and silent regions, accompanying H2A.X and opposed to H2A.Z/H2B.Z dimers

Pendulum limit, chaos and phase-locking in the dynamics of ac-driven semiconductor superlattices

We describe a limiting case when nonlinear dynamics of an ac-driven semiconductor superlattice in the miniband transport regime is governed by a periodically forced and damped pendulum. We find analytically the conditions for a transition to chaos and consider an influence of temperature on the effect. We also discuss fractional dc voltage states in a superlattice originating from phase-locked states of the pendulum.Comment: 8 pages, no figures. Version2 is strongly revised: new physics, more references. 3 appendixes of this Eprint are absent in the manuscript submitted to journa