scholarly journals Mie-Type Calculation of the Generalized Electromagnetic Nonlocal Conductivity Tensor for a Sphere and Its Equivalence to the T-Matrix Operator

2019 ◽  
Vol 2019 ◽  
pp. 1-20 ◽  
Author(s):  
E. Gutiérrez-Reyes ◽  
Rubén G. Barrera ◽  
A. García-Valenzuela
Keyword(s):  
Mean Field ◽  
Single Scattering ◽  
Conductivity Tensor ◽  
Field Theories ◽  
Electromagnetic Response ◽  
Magnetic Response ◽  
Type Calculation ◽  
The Mean ◽  
T Matrix ◽  
Nonlocal Conductivity

The purpose of this article is to calculate the generalized nonlocal conductivity tensor of a spherical particle made of isotropic and linear materials. The generalized conductivity tensor is a crucial element in the formulation of the mean-field theories of the electromagnetic response of random particulate systems. This is equivalent to what is called the T-Matrix in multiple scattering theories. Here, a new method is proposed for finding explicit expressions for this tensor directly from its definition including the magnetic response of the spheres. Its relation with the S-Matrix in the theory of single scattering is stated as a generalization. Several approximations and limit cases of possible interest in specific systems are analyzed and the results of some calculations are presented as a numerical example.

scholarly journals The Mean Field Theories of Magnetism and Turbulence

Entropy ◽  
2017 ◽  
Vol 19 (11) ◽  
pp. 589 ◽  
Author(s):  
Peter W. Egolf ◽  
Kolumban Hutter
Keyword(s):  
Mean Field ◽  
Field Theories ◽  
The Mean ◽  
Mean Field Theories

BULK PROPERTIES OF CHERN–SIMONS SUPERCONDUCTIVITY AT FINITE TEMPERATURES

1994 ◽  
Vol 08 (22) ◽  
pp. 3095-3135 ◽  
Author(s):  
S. S. MANDAL ◽  
S. RAMASWAMY ◽  
V. RAVISHANKAR
Keyword(s):  
Mean Field Theory ◽  
Free Field ◽  
Mean Field ◽  
Form Factors ◽  
Spin Correlation ◽  
Thermal Fluctuations ◽  
Correlation Factor ◽  
Electromagnetic Response ◽  
The Mean ◽  
Chern Simons

We study Chern–Simons (CS) superconductivity at finite temperatures for a system of two dimensional 'spin-1/2' fermions which are minimally coupled to both the CS and Maxwell gauge fields. We evaluate the electromagnetic response of the system as well as its thermodynamic properties within the mean field formalism. Our results for magnetic susceptibility, conductivity and dielectric constant show a sharp transition to the normal state over a narrow range of temperatures. The vanishing of the off-diagonal conductivity due to a corresponding fall in parity and time reversal [Formula: see text] violating correlation factor may be interpreted to be an effective restoration of [Formula: see text] symmetries in the macroscopic state. We find that the spin correlation function has a negligibly small numerical value at all temperatures, which implies that the thermal fluctuations dominate over the quantum fluctuations in the spin state. To explore the validity of mean field theory at high temperatures (HT), we compare the responses as well as the form factors for both mean field and free field (perturbative) formalism and find that they are essentially equivalent at HT. Finally, we present a coarse criterion for the validity of the mean field ansatz by regulating the CS Lagrangian with a Maxwell term.

Calculating field theories beyond the mean-field level

2006 ◽  
Vol 75 (3) ◽  
pp. 378-384 ◽  
Author(s):  
S. A Baeurle ◽  
G. V Efimov ◽  
E. A Nogovitsin
Keyword(s):  
Mean Field ◽  
Field Theories ◽  
Field Level ◽  
The Mean

Dielectric Relaxation Studies of 5PCH by the Time Domain Spectroscopy Method

1995 ◽  
Vol 50 (6) ◽  
pp. 595-600 ◽  
Author(s):  
Bo Gestblom ◽  
Stanislaw Urban
Keyword(s):  
Time Domain ◽  
Nematic Phase ◽  
Relaxation Times ◽  
Mean Field ◽  
Field Theories ◽  
Isotropic Phase ◽  
Time Domain Spectroscopy ◽  
Nematic State ◽  
The Mean ◽  
The Time Domain

Abstract The time domain spectroscopy (TDS) method has been used for the measurement of the complex dielectric permittivity in the isotropic phase and for perpendicular and parallel orientations in the nematic phase of 5PCH (4-(trans-4-pentyl-cyclohexyl)-benzonitrile). The accessible frequencies range from ca 15 MHz to ca. 1.5 GHz. The obtained spectra are well consistent with the spectra measured recently in the frequency domain (T. Brückert et al., Mol. Cryst. Liq. Cryst., in press). From the relaxation times τ‖, τ⊥and τis we have calculated the activation enthalpies and the retardation factors g|| and g⊥ that allow to obtain the nematic potential q. The validity of some assump­ tions of the mean-field theories of the nematic state are discussed.

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