Thermofield-Bosonization on Compact Space

We develop the construction of fermionic fields in terms of bosonic ones to describe free and interaction models in the circle, using thermofielddynamics. The description in the case of finite temperature is developed for both normal modes and zero modes. The treatment extends the thermofield-bosonization for periodic space

Neutron stars within a general relativistic theory including strong, weak and electromagnetic interactions

We construct the ground-state equilibrium configurations of neutron stars. The system of equilibrium equations is obtained taking into account quantum statistics, electro-weak, and strong interactions, within the framework of general relativity in the non-rotating spherically symmetric case. The core is assumed to be composed of interacting degenerate neutrons, protons and electrons in beta equilibrium. The strong interaction between nucleons is modeled through sigma-omega-rho meson exchange model. The mass-radius relation for neutron star cores is obtained for the various nuclear parametrizations. The mass and the thickness of the outer crusts corresponding to the different core mass-radius relations are obtained. The analysis is performed for two selected equations of state (EoS)of the outer crust matter. The first one neglects the Coulomb interactions between the degenerate electrons and the nuclear component of fixed charge to mass ratio Z/A. The second EoS, takes into account the Coulomb interactions of the point-like nuclei with a uniform fluid of degenerate electrons and the nuclear contribution is obtained from experimental data of nuclear masses. The mass and the thickness of the outer crust obtained with these two different EoS are compared and contrasted. We obtain systematically outer crusts with smaller mass and larger thickness when Coulomb interactions are taken into account

Higher-Derivative Two-Dimensional Massive Fermion Theories

We consider the canonical quantization of a generalized two-dimensional massive fermion theory containing higher odd-order derivatives. The requirements of Lorentz invariance, hermiticity of the Hamiltonian and absence of tachyon excitations suffice to fix the mass term, which contains a derivative coupling. We show that the basic quantum excitations of a higher-derivative theory of order 2N+1 consist of a physical usual massive fermion, quantized with positive metric, plus 2N unphysical massless fermions, quantized with opposite metrics. The positive metric Hilbert subspace, which is isomorphic to the space of states of a massive free fermion theory, is selected by a subsidiary-like condition. Employing the standard bosonization scheme, the equivalent boson theory is derived. The results obtained are used as a guideline to discuss the solution of a theory including a current-current interaction.Comment: 23 pages, Late

Evidenze altomedievali nelle valli dei fiumi Torto e Imera settentrionale

Si illustrano i risultati relativi al periodo altomedievale nell'area della Sicilia centro-settentrionale corrispondente ai bacini dei fiumi Torto e Imera settentrionale. I dati archeologici, frutto delle prospezioni qui condotte, testimoniano forme di popolamento rurale sparso, con poche eccezioni rappresentate da siti egemoni

Centrifugally driven electrostatic instability in extragalactic jets

The stability problem of the rotation induced electrostatic wave in extragalactic jets is presented. Solving a set of equations describing dynamics of a relativistic plasma flow of AGN jets, an expression of the instability rate has been derived and analyzed for typical values of AGNs. The growth rate was studied versus the wave length and the inclination angle and it has been found that the instability process is much efficient with respect to the accretion disk evolution, indicating high efficiency of the instability.Comment: 7 pages, 4 figure

New spatial mechanisms for the kinematic analysis of the tibiotalar joint

In virtually unloaded conditions, the tibiotalar (ankle) joint behaves as a single degree-of-freedom system, and two fibres within the calcaneal-fibular and tibio-calcaneal ligaments remain nearly isometric throughout the flexion arc. A relevant theoretical model also showed that three articular surfaces and two ligaments act together as a mechanism to control the passive kinematics. Two equivalent spatial parallel mechanisms were formulated, with ligament fibres assumed isometric and articulating surfaces assumed rigid, either as three sphere-plane contacts, or as a single spherical pair. Predicted and measured motion in three specimens compared fairly well. Important enhancement of this previous work is here presented, with more accurate experimental data, more anatomical model surfaces, and a more robust mathematical model

Hilbert Space of Isomorphic Representations of Bosonized Chiral QCD2QCD_2

We analyse the Hilbert space structure of the isomorphic gauge non-invariant and gauge invariant bosonized formulations of chiral $QCD_2$ for the particular case of the Jackiw-Rajaraman parameter $a = 2$. The BRST subsidiary conditions are found not to provide a sufficient criterium for defining physical states in the Hilbert space and additional superselection rules must to be taken into account. We examine the effect of the use of a redundant field algebra in deriving basic properties of the model. We also discuss the constraint structure of the gauge invariant formulation and show that the only primary constraints are of first class.Comment: LaTeX, 19 page