PROCEEDINGS OF THE PHYSICS CONFERENCE TIM  11
 CONDENSED MATTER



Preface: Physics Conference TIM  11
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 THEORETICAL PHYSICS


Topological BF models with maximal field spectra: Consistent selfinteractions
View Description Hide DescriptionTaking into account the recent developments in alternative descriptions of gravity via topological BF models, all consistent selfinteractions of such theories with maximal field spectra in D=4,5,6 are analyzed in order to facilitate further generalizations to an arbitrary D. For convenience, the deformation of the solution to the master equation in the context of the BRSTantifield formalism is used as a general method of constructing consistent interacting gauge field theories. Also, commonly used hypotheses on quantum field theories on Minkowski spacetimes are employed.

On the Lagrangian formalism in phasespace
View Description Hide DescriptionA secondorder approach to firstorder theories is addressed.

The anyon's knotted paths and M. Kontsevich integral
View Description Hide DescriptionIn this paper the topological quantum computing theory based on the evolution of the anyons in 2+1 spacetime is presented. The Kontsevich integrals are used as significant tools in analysing the behaviour of anyons which obey parastatistics. There are polynomial invariants describing the knotted 2+1 dimensional spacetime trajectories of the anyons and the present work tries to put all these into an adequate frame.

Physical degrees of freedom in theories with massless tensor gauge fields of degree two
View Description Hide DescriptionStarting from a generic secondorder Lagrangian (that describes the dynamics of an Abelian tensor gauge field of degree two and depends on two arbitrary real constants) we perform the Dirac analysis. This procedure determines the number of physical degrees of freedom and also a generating set of gauge transformations for the initial theory.

Elastic scattering of Xrays and gamma rays by 2S electrons in ions and neutral atoms
View Description Hide DescriptionThe nonrelativistic limit of Rayleigh scattering amplitude on 2s electrons of neutral and partially ionized atoms is obtained by making use of the Green Function method. The result takes into consideration the retardation, relativistic kinematics and screening effects. The spurious singularities introduced by the retardation in a nonrelativistic approach are cancelled by the relativistic kinematics. For neutral and partially ionized atoms, a screening model is considered with an effective charge obtained by fitting the HartreeFock charge distribution with pure Coulombian wave functions corresponding to a central potential of a nucleus with Z eff as the atomic number. The total cross section of the photoeffect on the 2s electrons is also calculated from the imaginary part of the forward scattering amplitude by means of the optical theorem. The numerical results obtained are in a good agreement (10%) with the ones obtained by Kissell for the Rayleigh amplitude and by Scofield for the Photoeffect total cross section on the 2s electrons, for atoms with atomic number 18 ≤ Z ≤ 92 and photon energies . (α=1/137,... is the fine structure constant, m is the electron mass).

About non standard Lagrangians in cosmology
View Description Hide DescriptionA review of non standard Lagrangians present in modern cosmological models will be considered. Well known example of non standard Lagrangian is DiracBornInfeld (DBI) type Lagrangian for tachyon field. Another type of non standard Lagrangian under consideration contains scalar field which describes open padic string tachyon and is called padic string theory Lagrangian. We will investigate homogenous cases of both DBI and padic fields and obtain Lagrangians of the standard type which have the same equations of motions as aforementioned non standard one.

Interaction between the molecular coherent states for a discrete variable harmonic oscillator and the coherent radiation
View Description Hide DescriptionWe used the dicrete variable threedimmensional Charlier oscillator. For a system of molecules interacting with the coherent radiation field the temporal variation of the refractive index has been established.

Quantum correlations in Gaussian open systems
View Description Hide DescriptionIn the framework of the theory of open systems based on completely positive quantum dynamical semigroups, we give a description of the quantum correlations of a system consisting of two noninteracting modes embedded in a thermal environment. We describe the evolution of the quantum entanglement in terms of the covariance matrix for Gaussian input states. For all values of the temperature of the thermal reservoir, an initial separable squeezed thermal state remains separable for all times. In the case of an entangled initial squeezed thermal state, entanglement suppression (entanglement sudden death) takes place, for nonzero temperatures of the environment. The Gaussian quantum discord, which is a measure of all quantum correlations in the state, including entanglement, decays asymptotically in time under the effect of the thermal bath.

Generalized coherent states for polynomial WeylHeisenberg algebras
View Description Hide DescriptionIt is the aim of this paper to show how to construct á la Perelomov and á la BarutGirardello coherent states for a polynomial WeylHeisenberg algebra. This algebra depends on r parameters. For some special values of the parameter corresponding to r = 1, the algebra covers the cases of the su(1,1) algebra, the su(2) algebra and the ordinary WeylHeisenberg or oscillator algebra. For r arbitrary, the generalized WeylHeisenberg algebra admits finite or infinitedimensional representations depending on the values of the parameters. Coherent states of the Perelomov type are derived in finite and infinite dimensions through a FockBargmann approach based on the use of complex variables. The same approach is applied for deriving coherent states of the BarutGirardello type in infinite dimension. In contrast, the construction of á la BarutGirardello coherent states in finite dimension can be achieved solely at the price to replace complex variables by generalized Grassmann variables. Finally, some preliminary developments are given for the study of Bargmann functions associated with some of the coherent states obtained in this work.

The influence of the dynamic localization on the time dependent oscillations of currents on the one dimensional lattice
View Description Hide DescriptionThe propagation of electrons on the 1D lattice under the influence of dcac electric fields is discussed in terms of discretized currents. In the dynamic localization regime the time dependence of such currents gets characterized by regular periodic oscillations. Going beyond dynamic localizations leads, to the onset of aperiodic oscillations. The time dependence of the mean square displacement is also discussed. We found that in the regime of dynamic localization the current and the MSD exhibit the same zero’s. Typical plots concerning the time dependence of such oscillations have been displayed.

Excited binomial states for the pseudoharmonic oscillator
View Description Hide DescriptionWe have examined some properties of a linear superposition of the binomial states (BSs), in the basis of Fock  vectors which correspond to the pseudoharmonic oscillator (PHO). These states have all the properties of usual coherent states (CSs). We have defined the excited binomial states (EBSs) for the PHO, by repeatedly application of the SU(1, 1) raising operator on the nonexcited BSs, which is considered the "fundamental" state. Also we have examined the expectation values in the EBSs  basis, especially of the integer powers of the number operator, which is useful to calculate the Mandel's parameter. Depending on the value of this parameter, we can conclude about the statistical behavior of the EBCs: subPoissonian, Poissonian or superPoissonian.

Selfdual 3forms: Gauge unfixing approach
View Description Hide DescriptionThe problem of quantization of selfduals 3forms is considered in the framework of the gauge unfixing approach based on path integral. Starting from the original secondclass theory, selfdual 3forms, we construct a firstclass theory. With firstclass theory at hand, we build the corresponding Hamiltonian path integral. The Hamiltonian path integral of the firstclass system takes a manifestly Lorentzcovariant form after integrating out the auxiliary fields and performing some field redefinitions. For different kinds of phasespace extensions we identify the Lagrangian path integral for 2and 3forms with Stückelberglike coupling or the Lagrangian path integral for two kinds of 3forms with topologicallike coupling.

Energy band structures for electrons on the triangular lattice with uniform magnetic field
View Description Hide DescriptionIn the present paper the electron on the triangular lattice with uniform perpendicular magnetic field [1,2] is considered. The energy band structure is visualized using numerical computations. The energy bands as a function of the magnetic field display a Hofstadter butterfly [3,4] type diagram. The influence of the hopping parameters on the energy spectra is also taken into account.

The path integral formalism applied on the quantum rigid rotator
View Description Hide DescriptionIn this paper we apply the path integral formalism for the quantum rigid rotator in 2+1 space time dimension related to the knot theory. The knots theory put the knots into an one to one relation with the braids considered in the braid group theory where braids are actually path into the path integrals formalism. The present work aims the connection between such theories and the anyons behavior.

 CONDENSED MATTER


Modeling of crystal field and spinHamiltonian parameters for tetrahedral coordinated doped in
View Description Hide DescriptionIn this paper we modeled the crystal field and spinHamiltonian parameters for tetrahedral coordinated doped in host matrix. The numerical theoretical crystal field parameters were computed with site symmetry of the impurity ions, in the frame of the superposition model of crystal field, taking into account the effects of the bond formation between the and first coordination sphere of ions coordination. The Hamiltonian of the : system has been diagonalized in a complete basis set spanned by all wave functions of the 3d^{2} electron configuration. The obtained results give a satisfactory agreement with experimental data. The spinHamiltonian parameters of the system (g _{‖}, g _{⊥} factors and for D zero field splitting energy) are calculated in perturbation theory method, and good agreement with experimental data is obtained.

Mathematica® code for StonerWohlfarth processes
View Description Hide DescriptionA simple and robust numeric code written in Mathematica® is proposed in order to generate magnetic hysteresis loops and critical curves in the framework of the StonerWohlfarth model, extended to take into account the effect on an external mechanical stress; a case study referring to the influence of the shear stress applied normal to the magnetic field direction is presented.

THztime domain spectroscopy of (001) ZnSe
View Description Hide DescriptionTerahertz absorbance in (001) ZnSe has been experimentally studied using a femtosecond (fs) pulse train emitted from a self mode lock fiber laser. Preliminary results suggest three different regions for the phase and two different behaviors. The Drude model calculations of the complex conductivity suggest a collision frequency Δf around 0.06 THz.

Symmetry and charge factor in ion doped compounds
View Description Hide DescriptionSymmetry and electrostatic equilibrium in lanthanide compounds are discussed with the aim of improving the role of obtaining the charge factors, g j , of the nearest neighbours (NN) of the lanthanide site, j running over the NN, now using the g j vs R j (the NN position) linear behaviour. The simple overlap model (SOM) and the method of equivalent nearest neighbours (MENN), are used in order to calculate the crystal field parameters and the ^{7}F1 level splitting in complexes, crystals and glass. An inferior limit of the g j position is predicted for crystals and complexes, which is around the limit of 5s and 5p filled shells and may indicate different contraction/extension of the 4f wave functions. Further, it is discussed the possibility that, perhaps, the B ^{ 4 } q and B ^{ 6 } q parameters are not dependent on R j in the same way as the B ^{ 2 } q parameter is.
