scholarly journals Drastic advancement in nanophotonics achieved by a new dressed photon study

2021 ◽  
Vol 17 (1) ◽  
Author(s):  
Hirofumi Sakuma ◽  
Izumi Ojima ◽  
Motoichi Ohtsu ◽  
Tadashi Kawazoe
Keyword(s):  
Degrees Of Freedom ◽  
Thought Experiment ◽  
Theoretical Models ◽  
Theoretical Explanation ◽  
Research Directions ◽  
Timely Review ◽  
Mathematical Equations ◽  
Preliminary Study ◽  
Specific Implementation ◽  
New Phase

Abstract On the very recent advancement of dressed photon studies A timely review of the emerging new phase of dressed photon (DP) studies, not yet prevailing in the global nanophotonic society, is given in contradistinction to its preceding incipient phase. A new theory on DPs crucially depends on a couple of important elements, namely, the knowledge on quantum field theory (QFT) having infinite degrees of freedom, notably on the micro-macro duality (MMD) theory developed by Ojima, and a newly proposed Clebsch dual (CD) electromagnetic field as a specific implementation of MMD theory. The main aim of the first part of this article after the introduction, the section of “In search of refinement of the theoretical models”, is twofold: to explain plainly, without resorting to mathematical equations, the essence of the highly mathematical contents of MMD theory, which clarifies a problematic aspect of the Schrödinger’s cat thought experiment, and to explain the physical meanings of the CD field. Preliminary study on the existence of DP light with spin zero In the section of “Observed “photon cluster” and light field with spin zero”, we briefly report a new intriguing experimental discovery implying the existence of propagating particle-like “quantum DP light” together with a conjecture on its possible theoretical explanation. A perspective on a variety of possible research directions for DPs is then briefly mentioned in mentioned in the final section.

School Counselor Assignment in Secondary Schools

2009 ◽  
Vol 13 (1) ◽  
pp. 2156759X0901300
Author(s):  
Patrick Akos ◽  
Heidi Schuldt ◽  
Meg Walendin
Keyword(s):  
Secondary Schools ◽  
School Counselors ◽  
School Counselor ◽  
Professional School ◽  
Future Research ◽  
Research Directions ◽  
Secondary School Counselors ◽  
Significant Difference ◽  
Future Research Directions ◽  
Preliminary Study

Research has not yet begun to investigate the practice or impact of school counselor assignment. A preliminary study sought to explore the nature and consequences of school counselor assignment practices in secondary schools. Secondary school counselors from one large Southeastern school district were asked to complete a questionnaire created for the purpose of this study. The results suggest a significant difference between school counselor assignment at the middle and high school levels. Middle schools predominantly utilized grade-level assignment while high schools used alphabetical assignment. Distinct advantages and challenges were indicated by school counselors from each assignment type. Implications for professional school counselors and future research directions are provided.

scholarly journals The Ground-State Calculations for Some Nuclei by Mesonic Potential of Nucleon-Nucleon Interaction

2020 ◽  
Vol 2020 ◽  
pp. 1-15
Author(s):  
K. M. Hanna ◽  
S. H. M. Sewailem ◽  
R. Hussien ◽  
L. I. Abou-Salem ◽  
Asmaa G. Shalaby
Keyword(s):  
Ground State ◽  
Degrees Of Freedom ◽  
Vector Fields ◽  
Theoretical Models ◽  
Nucleon Nucleon ◽  
Particle Energy ◽  
Exchange Potential ◽  
Hartree Fock ◽  
Scalar And Vector Fields ◽  
Nucleon Nucleon Interaction

The interaction of nucleon-nucleon (NN) has certain physical characteristics, indicated by nucleon, and meson degrees of freedom. The main purpose of this work is calculating the ground-state energies of  12H and  24He through the two-body system with the exchange of mesons (π, σ, and ω) that mediated between two nucleons. This paper investigates the NN interaction based on the quasirelativistic decoupled Dirac equation and self-consistent Hartree-Fock formulation. We construct a one-boson exchange potential (OBEP) model, where each nucleon is treated as a Dirac particle and acts as a source of pseudoscalar, scalar, and vector fields. The potential in the present work is analytically derived with two static functions of meson, the single-particle energy-dependent (SPED) and generalized Yukawa (GY) functions; the parameters used in meson functions are just published ones (mass, coupling constant, and cutoff parameters). The theoretical results are compared to other theoretical models and their corresponding experimental data; one can see that the SPED function gives more satisfied agreement than the GY function in the case of the considered nuclei.

THEORETICAL MODELS FOR MAGNETIC PROPERTIES OF IRON PNICTIDES

2013 ◽  
Vol 27 (16) ◽  
pp. 1350071 ◽  
Author(s):  
M. VUJINOVIĆ ◽  
M. PANTIĆ ◽  
D. KAPOR ◽  
P. MALI
Keyword(s):  
Magnetic Properties ◽  
Heisenberg Model ◽  
Degrees Of Freedom ◽  
Random Phase ◽  
Three Dimensional ◽  
Theoretical Models ◽  
Wave Dispersion ◽  
Model Parameters ◽  
Neel Temperature ◽  
Néel Temperature

We attempt to describe the magnetic properties of parent pnictide compounds by using both the J1–J2 Heisenberg model and its three-dimensional generalization, the J1–J2–Jc model. We also include spin anisotropy in the XY plane. In order to obtain the average magnetization and spin wave dispersion, we use the Green's functions method for spin operators in the random phase approximation. We obtain estimates for the model parameters by considering the low temperature experimental dispersion for the compounds CaFe 2 As 2 and BaFe 2 As 2 and conclude that theoretical dispersion can fit the experimental one if spatially anisotropic Hamiltonian is used. A good agreement between theory and experiment indicates that the Heisenberg model is applicable to parent pnictides at low temperatures. The applicability of the model for higher temperatures is checked by calculating the Néel temperature for both compounds. It turns out that the model overestimates the measured critical temperature. The Heisenberg model is not applicable to parent pnictides, for temperature comparable to Néel temperature. Our results thus confirm that all the magnetic properties of parent pnictides cannot be described with purely localized degrees of freedom, and that the itinerant magnetism should have an important role in these compounds. All results given in Sec. 3 are general and could be used in description of classes of compounds with spin stripe structure.

scholarly journals Clusters as surrogate for explicit short-range correlations in relativistic mean-field models

2020 ◽  
Vol 229 (22-23) ◽  
pp. 3433-3444
Author(s):  
Stefan Typel
Keyword(s):  
Nuclear Matter ◽  
Density Functional ◽  
Degrees Of Freedom ◽  
Present Model ◽  
Mean Field ◽  
Theoretical Models ◽  
Density Functionals ◽  
Many Body ◽  
Relativistic Mean Field ◽  
Short Range Correlations

AbstractThe formation of clusters at sub-saturation densities in nuclear matter can be seen as a result of many-body correlations. Various theoretical models have been developed to take this effect into account, mostly on a phenomenological level using energy density functionals. These models are constructed in such a way that clusters appear solely in dilute matter and dissolve when the density approaches the nuclear saturation density. At higher densities only nucleons survive as quasi-particles and no explicit correlations between the constituents of nuclear matter are considered. The possible description of correlations with cluster degrees of freedom at supra-saturation densities is explored using the example of a quasi-deuteron in a generalized relativistic density functional. The required change in the density dependence of the cluster mass shift, responsible for describing the cluster dissolution in the present model, is derived for nuclear matter at zero temperature.

scholarly journals Implementation and Validation of a Potential Model for a Moored Floating Cylinder under Waves

2020 ◽  
Vol 8 (2) ◽  
pp. 131 ◽  
Author(s):  
Maria Gabriella Gaeta ◽  
Giacomo Segurini ◽  
Adrià M. Moreno ◽  
Renata Archetti
Keyword(s):  
Degrees Of Freedom ◽  
Domain Model ◽  
Mooring System ◽  
Floating Bodies ◽  
Wave Flume ◽  
Preliminary Study ◽  
The Time Domain ◽  
The University ◽  
The Mathematical Model ◽  
Three Degrees Of Freedom

A three degrees-of-freedom model based on the potential flow theory was implemented to represent the motion of a slender cylindrical buoy under waves. The model calibration was performed by means of the comparison between the model results and the experiments performed at the Laboratory of Hydraulic Engineering of the University of Bologna (Italy). The dynamics of the floating cylinder, placed at the mid-section of the wave flume and anchored at the bottom through a mooring system of four catenaries, were obtained through videography analysis, providing surge, heave and pitch motions. The implementation of the mathematical model consisted of two main parts: The first has been developed in the frequency domain by applying NEMOH to assess the hydrodynamic coefficients of the object, i.e., the excitation, radiation and added mass coefficients; then, the used mooring system was included in the time-domain model, solving the motion of the floating cylinder, by calibrating the mooring coefficients by comparing the results with the data. The simplicity of the implemented model is a very important feature, and it should be used as a preliminary study to understand the response of moored floating cylinders and others floating bodies under waves.

Preliminary Study of a Centrifugal Compressor With Counter-Rotating Impellers: Design and Performances Study

2020 ◽  
Author(s):  
Abed Cheikh Brahim ◽  
Khelladi Sofiane ◽  
Deligant Michael ◽  
El Marjani Abdel ◽  
Farid Bakir
Keyword(s):  
Centrifugal Compressor ◽  
Degrees Of Freedom ◽  
Numerical Data ◽  
Centrifugal Impeller ◽  
Through Flow ◽  
Aerodynamic Performances ◽  
Preliminary Study ◽  
And Performance ◽  
And Control ◽  
Selection Of

Abstract Turbomachinery with double counter-rotating impellers offer more degrees of freedom in the choice of design and control parameters compared to conventional machines. For these innovative machines, the literature review shows that more published works are available concerning axial type turbomachines than centrifugal ones. This work deals with a preliminary design and performance analysis applied to two counter-rotating impellers of a centrifugal compressor. We present here the design practice developed based on 0D/1D models, also coupled with optimization and stream-curvature through-flow methods to satisfy the selected design-criteria. An analyze of aerodynamic performances results are made and compared to those available experimental and numerical data of a baseline configuration, composed of one centrifugal-impeller and a volute. The compressor studied here includes a first conventional impeller with an axial inlet and a mixed or centrifugal outlet. The second impeller is designed parametrically and can be considered as a rotating-diffuser with a radial or mixed inlet and outlet. Ultimately, the numerical simulation results of a selection of candidate solutions are discussed.

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