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At least 1,297 records · Page 72

Foundation of Hydrodynamics for Systems with Strong Interactions

For a dense and strongly interacting system, such as a nucleus or a strongly-coupled quark-gluon plasma, the foundation of hydrodynamics can be better found in the quantum description of constituents moving in the strong mean fields generated by all other particles. Using the result that the Schroedinger equation and the Klein-Gordon equation can be written in hydrodynamical forms, we find that the probability currents of the many-body system in the mean-field description obey a hydrodynamical equation with stress tensors arising from many contributions: quantum effects, mean-field interactions, and thermal fluctuations. The influence of various contributions to the hydrodynamical motion is expected to vary with the temperature, as the quantum and mean-field stress tensors playing more important roles at low and moderate temperatures.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗

'Number States' and 'Pilot Waves' Hidden in Maxwell's Classical Equations

Schroedingers equation with boundary conditions gives quantized energy states for electron waves, but Maxwell's wave equations have quantized states only by analogies with harmonic oscillators. This problem is addressed by a novel theory of wave-packets using diffracting Transverse Electric and Transverse Magnetic fields defined by axial H- and E-fields. All transverse fields and gradient operators can together be rotated about the propagation axis at frequencies, independent of the modal frequency. Without altering the axial fields, any helical motion propagates at the group velocity. This is quite different from single frequency helical modes (e.g. Laguerre Gaussian) travelling at the phase velocity. Reversing time and frequency, allows counter rotating helical solutions. These are referred to as adjoint or a fields that may interact and propagate with the classical causal reference or r fields. Overlapping and counter rotating r and a fields with slightly different frequencies interfere, leaving circular polarization states unaltered and creating a nodal structure in the transverse fields distinct from the nodal structure in the axial fields. Number states arise from requiring that transverse and axial nodes co-locate with integral spacings to form a wave-packet,. The a fields act as pilot waves for future potential positions of a quantized interaction between r and a fields. Uncertainty in the position of the overlap leads to conventional probabilistic quantum interpretations. The a fields are not fully determined until their detection with the r wave and this late determination can offer explanations for non-local entanglement.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗

Inerton fields: very new ideas on fundamental physics

Modern theories of everything, or theories of the grand unification of all physical interactions, try to describe the whole world starting from the first principles of quantum theory. However, the first principles operate with undetermined notions, such as the wave {psi}-function, particle, lepton and quark, de Broglie and Compton wavelengths, mass, electric charge, spin, electromagnetic field, photon, gravitation, physical vacuum, space, etc. From a logical point of view this means that such modern approach to the theory of everything is condemned to failure... Thus, what should we suggest to improve the situation? It seems quite reasonable to develop initially a theory of something, which will be able to clarify the major fundamental notions (listed above) that physics operates with every day. What would be a starting point in such approach? Of course a theory of space as such, because particles and all physical fields emerge just from space. After that, when a particle and fields (and hence the fields' carriers) are well defined and introduced in the well defined physical space, different kinds of interactions can be proposed and investigated. Moreover, we must also allow for a possible interaction of a created particle with the space that generated the appearance of the particle. The mathematical studies of Michel Bounias and the author have shown what the real physical space is, how the space is constituted, how it is arranged and what its elements are. Having constructed the real physical space we can then derive whatever we wish, in particular, such basic notions as mass, particle and charge. How are mechanics of such objects (a massive particle, a charged massive particle) organised? The appropriate theory of motion has been called a sub microscopic mechanics of particles, which is developed in the real physical space, not an abstract phase space, as conventional quantum mechanics does. A series of questions arise: can these two mechanics (submicroscopic and conventional quantum mechanics) be unified?, what can such unification bring new for us?, can such submicroscopic mechanics be a starting point for the derivation of the phenomenon of gravity?, can this new theory be a unified physical theory?, does the theory allow experimental verification? These major points have been clarified in detail. And, perhaps, the most intriguing aspect of the theory is the derivation of a new physical field associated with the notion of mass (or rather inertia of a particle, which has been called the inerton field and which represents a real sense of the particle's wave {psi}-function). This field emerges by analogy with the electromagnetic field associated with the notion of the electric charge. Yes, the postulated inerton field has being tested in a series of different experiments. Even more, the inerton field might have a number of practical applications...

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗

The Cumulative Effect of Vacuum Radiation on Particle Coordinates

The action principle can predict the trajectories of a system of particles as determined by the dynamical forces acting on them. However, its predictions do not include the results of quantum fluctuations in the coordinates of the particles. It is proposed that quantum fluctuations shift the particles from one dynamical trajectory to another and that the change in action due to a root mean square shift in an individual coordinate is the same, regardless of which coordinate is shifted. This assumption, together with the uncertainty principle, implies that the cumulative effect of changes in energy and momentum varies as t{sup -1/2}, where t is time, so that these quantities tend to be conserved. However, the cumulative effect of changes in spatial coordinate varies as t{sup 1/2}, so this coordinate shows a Brownian drift over time. An example is given in which this stochastic drift, with its characteristic t{sup 1/2} dependence, could be experimentally observed at the beginning of a highly collimated particle beam.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗

QCD and Effective Locality

A new, functional approach to analytic, non-perturbative, gauge-invariant QCD.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗

Nonleptonic B{sub s} to charmonium decays and their role in the determination of the {beta}{sub s}

This talk consists of two parts. We first present a light-cone QCD sum rule computation of the B{sub s{yields}}f{sub 0}(980) form factors which are necessary inputs in semileptonic and nonleptonic Bs decays into f{sub 0}(980). Then we analyze nonleptonic B{sub s} decays into a charmonium state and a light meson, which are potentially useful to access the B{sub s}-B-bar{sub s} mixing phase {beta}{sub s}. We explore the experimental feasibility of measuring these various channels, paying attention to different determinations of {beta}{sub s} in view of the hints of new physics recently emerged in the B{sub s} sector.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗

The harmonic oscillator and the position dependent mass Schroedinger equation: isospectral partners and factorization operators

One of the most important scientific contributions of Professor Marcos Moshinsky has been his study on the harmonic oscillator in quantum theory vis a vis the standard Schroedinger equation with constant mass [1]. However, a simple description of the motion of a particle interacting with an external environment such as happen in compositionally graded alloys consist of replacing the mass by the so-called effective mass that is in general variable and dependent on position. Therefore, honoring in memoriam Marcos Moshinsky, in this work we consider the position-dependent mass Schrodinger equations (PDMSE) for the harmonic oscillator potential model as former potential as well as with equi-spaced spectrum solutions, i.e. harmonic oscillator isospectral partners. To that purpose, the point canonical transformation method to convert a general second order differential equation (DE), of Sturm-Liouville type, into a Schroedinger-like standard equation is applied to the PDMSE. In that case, the former potential associated to the PDMSE and the potential involved in the Schroedinger-like standard equation are related through a Riccati-type relationship that includes the equivalent of the Witten superpotential to determine the exactly solvable positions-dependent mass distribution (PDMD)m(x). Even though the proposed approach is exemplified with the harmonic oscillator potential, the procedure is general and can be straightforwardly applied to other DEs.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗

Conformal mapping and bound states in bent waveguides

Is it possible to trap a quantum particle in an open geometry? In this work we deal with the boundary value problem of the stationary Schroedinger (or Helmholtz) equation within a waveguide with straight segments and a rectangular bending. The problem can be reduced to a one-dimensional matrix Schroedinger equation using two descriptions: oblique modes and conformal coordinates. We use a corner-corrected WKB formalism to find the energies of the one-dimensional problem. It is shown that the presence of bound states is an effect due to the boundary alone, with no classical counterpart for this geometry. The conformal description proves to be simpler, as the coupling of transversal modes is not essential in this case.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗

Symmetry breaking: a tool to unveil the topology of chaotic scattering with three degrees of freedom

We shall use symmetry breaking as a tool to attack the problem of identifying the topology of chaotic scatteruing with more then two degrees of freedom. specifically we discuss the structure of the homoclinic/heteroclinic tangle and the connection between the chaotic invariant set, the scattering functions and the singularities in the cross section for a class of scattering systems with one open and two closed degrees of freedom.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗

Doorway states and billiards

Whenever a distinct state is immersed in a sea of complicated and dense states, the strength of the distinct state, which we refer to as a doorway, is distributed in their neighboring states. We analyze this mechanism for 2-D billiards with different geometries. One of them is symmetric and integrable, another is symmetric but chaotic, and the third has a capricious form. The fact that the doorway-state mechanism is valid for such highly diverse cases, proves that it is robust.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗

Usage Of New Activation Function In Neuro-Symbolic Integration

New activation function is examined for its ability to accelerate the performance of doing logic programming in Hopfield network. This method has a higher capacity and upgrades the neuro symbolic integration. Computer simulations are carried out to validate the effectiveness of the new activation function. Empirical results obtained support our theory.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗

Volterra network modeling of the nonlinear finite-impulse reponse of the radiation belt flux

We show how a general class of spatio-temporal nonlinear impulse-response forecast networks (Volterra networks) can be constructed from a taxonomy of nonlinear autoregressive integrated moving average with exogenous inputs (NAR-MAX) input-output equations, and used to model the evolution of energetic particle f uxes in the Van Allen radiation belts. We present initial results for the nonlinear response of the radiation belts to conditions a month earlier. The essential features of spatio-temporal observations are recovered with the model echoing the results of state space models and linear f nite impulse-response models whereby the strongest coupling peak occurs in the preceding 1-2 days. It appears that such networks hold promise for the development of accurate and fully data-driven space weather modelling, monitoring and forecast tools.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗

Collimator Magnet with Functionally Defined Profile for Ion Implantation

Advanced implantation systems used for semiconductor processing should have high precision of ion beam collimation (+/-0.1 deg and better) and wide beam aperture (400 mm and more). Typical arrangements of ion implantation systems include beam scanning (BSM) and collimator magnets (CM). Standard collimator magnets have limited precision of beam collimation due to magnetic poles that have piecewise circular profile. This study proposes a novel ''constant sum angle collimator magnet''(CSACM) with non-circular magnetic pole profile. Angles of incidence {alpha}{sub i} and exit {alpha}{sub e} are defined as angles between ion trajectory and local normal to CM input/output magnetic pole edge. Profile of the CSACM is defined as having constant algebraic sum {alpha}{sub i}+{alpha}{sub e} = const for every ion trajectory of the scanned beam, in addition to ''usual'' beam collimation. An iterative procedure allows improve CSACM taking into account magnetic fringe field effects. Simulation results prove that CSACM assures precise beam collimation in two orthogonal planes. Circular approximations for CSACM magnetic poles are proposed. The model may be further developed for global design of the ion beam line (BSM+CM) and for taking into account space-charge effects.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗

Effect of Equal Biaxial Pre-Strain on Forming Limit Diagram of AA5083

In this work, the effect of equal biaxial pre-strain on the forming limit curve (FLC) of 5083 aluminum alloy has been investigated. For this purpose, in the first stage, square blanks with dimensions of 200 mm in each length were cut from the original sheet and stretched by a spherical punch to the specified heights. Then, specimens were prepared by cutting the pre-strained blanks with the longitudinal axis parallel and perpendicular to the rolling direction. In the second stage, the specimens were tested by the out-of-plane test method to determine the forming limit diagram (FLD) according to the ISO 12004. Furthermore, forming limit stress diagram (FLSD) was determined by using Hill's quadratic yield function. The results showed that the equal biaxial pre-straining decreased and shifted the FLC to the right hand side of the diagram. However, it had not any effect on the forming limit stress curves.

36 MATERIALS SCIENCE↗

Utility Theory for Evaluation of Optimal Process Condition of SAW: A Multi-Response Optimization Approach

Multi-objective optimization problem has been solved in order to estimate an optimal process environment consisting of optimal parametric combination to achieve desired quality indicators (related to bead geometry) of submerged arc weld of mild steel. The quality indicators selected in the study were bead height, penetration depth, bead width and percentage dilution. Taguchi method followed by utility concept has been adopted to evaluate the optimal process condition achieving multiple objective requirements of the desired quality weld.

36 MATERIALS SCIENCE↗

Pearson's Functions to Describe FSW Weld Geometry

Friction stir welding (FSW) is a relatively new joining technique particularly for aluminium alloys that are difficult to fusion weld. In this study, the geometry of the weld has been investigated and modelled using Pearson's functions. It has been demonstrated that the Pearson's parameters (mean, standard deviation, skewness, kurtosis and geometric constant) can be used to characterize the weld geometry and the tensile strength of the weld assembly. Pearson's parameters and process parameters are strongly correlated allowing to define a control process procedure for FSW assemblies which make radiographic or ultrasonic controls unnecessary. Finally, an optimisation using a Generalized Gradient Method allows to determine the geometry of the weld which maximises the assembly tensile strength.

36 MATERIALS SCIENCE↗

On the grade consistent theories of micromorphic elastic solids

For the investigation of specific nonlocal phenomena the second-order displacement gradient has been added to the independent constitutive variables used in the classical theories of elastic solids. In this paper we outline the hystorical development of the subject and present a nonlinear grade consistent theory of micromorphic elastic solids in which the independent constitutive variables are the deformation gradient, the second-order displacement gradient, microdeformation tensor, and microdeformation gradient. Then, we present the linearized theory and establish a uniqueness result with no definiteness assumption on the elastic coefficients. The theory is used to obtain the basic eqations of a grade consistent theory of microstretch elastic bodies. The field equations for an isotropic and homogeneous elastic body are presented. A counterpart of the Cauchy-Kowalevski-Somigliana solution of the classical elastodynamics is established.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗

The isotropic Hamiltonian formalism

A Hamiltonian formalism is a procedure that allows to associate a dynamical system to a function and that includes classical Hamiltonian mechanics as a particular case. The present, expository paper gives a survey of the Hamiltonian formalism defined by an isotropic subbundle of TM+T*M, in particular, by a Dirac structure. We discuss reduction and geometric quantization of the Hamiltonian dynamical systems provided by this formalism.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗