scholarly journals Perspective: Coulomb fluids—Weak coupling, strong coupling, in between and beyond

2013 ◽  
Vol 139 (15) ◽  
pp. 150901 ◽  
Author(s):  
Ali Naji ◽  
Matej Kanduč ◽  
Jan Forsman ◽  
Rudolf Podgornik
Keyword(s):  
Strong Coupling ◽  
Weak Coupling ◽  
Coulomb Fluids

THE RELATION BETWEEN CHIRAL SYMMETRY SPONTANEOUSLY BREAKING AND CONFINEMENT IN QED

2001 ◽  
Vol 16 (12) ◽  
pp. 2253-2266
Author(s):  
KOU SU-PENG
Keyword(s):  
Strong Coupling ◽  
Chiral Symmetry ◽  
Dimensional Reduction ◽  
Weak Coupling ◽  
Coupling Phase ◽  
Fermion Pairs ◽  
Two Phases

In this paper, we use Parisi and Sourlas dimensional reduction to show that QED has two phases, the strong coupling phase and weak coupling phase. Because chiral symmetry is spontaneously broken, particles with fractional charges are confined in the strong coupling phase by the condensation of topological configurations, and particles with integer charges are screened by fermion pairs.

Weak Coupling Strategy for Multi-Physics CFD Simulation in Engineering Problems

2011 ◽  
Author(s):  
Makoto Yamamoto ◽  
Masaya Suzuki
Keyword(s):  
Strong Coupling ◽  
Time Scale ◽  
Weak Coupling ◽  
Particle Deposition ◽  
Cfd Simulation ◽  
The Other ◽  
Cfd Simulations ◽  
Sand Erosion ◽  
Coupling Strategy ◽  
The Difference

Multi-Physics CFD Simulation will be one of key technologies in various engineering fields. There are two strategies to simulate a multi-physics phenomenon. One is “Strong Coupling”, and the other is “Weak Coupling”. Each can be employed, based on time-scales of physics embedded in a problem. That is, when a time-scale of one physics is nearly same as that of the other physics, we have to use Strong Coupling to take into account the interaction between two physics. On the other hand, when one time-scale is quite different from the other one, Weak Coupling can be applied. Considering the present computer performance, Strong Coupling is difficult to be used in engineering design processes now. Therefore, we are focusing on Weak Coupling, and it has been applied to a number of multi-physics CFD simulations in engineering. We have successfully simulated sand erosion, ice accretion, particle deposition, electro-chemical machining and so on, with using Weak Coupling method. In the present study, the difference between strong and weak couplings is briefly described, and two examples of our multi-physics CFD simulations are expressed. The numerical results indicate that Weak Coupling strategy is promising in a lot of multi-physics CFD simulations.

scholarly journals Phases of a strongly coupled four-fermion theory

2018 ◽  
Vol 175 ◽  
pp. 03004 ◽  
Author(s):  
David Schaich ◽  
Simon Catterall
Keyword(s):  
Strong Coupling ◽  
Weak Coupling ◽  
Strongly Coupled ◽  
Coupling Phase ◽  
Long Range Correlations ◽  
Mass Gap ◽  
Narrow Region ◽  
Lattice Field ◽  
Lattice Symmetry ◽  
Lattice Fermion

We present ongoing investigations of a four-dimensional lattice field theory with four massless reduced staggered fermions coupled through an SU(4)-invariant fourfermion interaction. As in previous studies of four-fermion and Higgs–Yukawa models with different lattice fermion discretizations, we observe a strong-coupling phase in which the system develops a mass gap without breaking any lattice symmetry. This symmetric strong-coupling phase is separated from the symmetric weak-coupling phase by a narrow region of four-fermi coupling in which the system exhibits long-range correlations.

A Comparison of Strong and Weak Coupling Schemes for Computational Aeroelasticity in OpenFOAM

2018 ◽  
Author(s):  
Sabet Seraj ◽  
Amin Fereidooni ◽  
Anant Grewal
Keyword(s):  
Rigid Body ◽  
Strong Coupling ◽  
Weak Coupling ◽  
Body Motion ◽  
Coupling Scheme ◽  
Lower Sensitivity ◽  
Step Size ◽  
Time Step ◽  
Time Step Size ◽  
Structure Interaction

Two coupling schemes for fluid-structure interaction using the OpenFOAM structural solver sixDoF Rigid Body Motion are developed. The first scheme is developed by modifying the baseline leapfrog weak coupling scheme to minimize the lag between the fluid and structural solvers. The second is a strong coupling scheme based on the Crank-Nicolson method. The two newly implemented schemes and the baseline are compared through the aeroelastic simulation of a NACA 64A010 airfoil and the Benchmark Supercritical Wing. The aeroelastic solutions obtained using the newly implemented schemes exhibit significantly lower sensitivity to changes in time step size compared to the baseline weak coupling scheme. The modified weak coupling and strong coupling schemes perform comparably for the cases studied.

scholarly journals Ratio of Quark Masses in Duality Theories

2003 ◽  
Vol 18 (25) ◽  
pp. 1743-1752
Author(s):  
G. Cleaver ◽  
K. Tanaka
Keyword(s):  
Strong Coupling ◽  
Duality Theory ◽  
Weak Coupling ◽  
Singular Points ◽  
Bare Mass ◽  
Coupling Region ◽  
Quark Masses ◽  
Mass Ratios ◽  
Quark Flavors

We consider N=2 SU(2) Seiberg–Witten duality theory for models with N f =2 and N f =3 quark flavors. We investigate arbitrary large bare mass ratios between two or three quarks at the singular points. For N f =2 we explore large bare mass ratios corresponding to a singularity in the strong coupling region. For N f =3 we determine the location of both strong and weak coupling singularities that produce specific large bare mass ratios.

scholarly journals On bulk viscosity at weak and strong ’t Hooft couplings

2020 ◽  
Vol 35 (27) ◽  
pp. 2030012
Author(s):  
Alina Czajka ◽  
Keshav Dasgupta ◽  
Charles Gale ◽  
Sangyong Jeon ◽  
Aalok Misra ◽  
...  
Keyword(s):  
Boltzmann Equation ◽  
Kinetic Theory ◽  
Strong Coupling ◽  
Bulk Viscosity ◽  
Transport Coefficient ◽  
Weak Coupling ◽  
Coupling Analysis ◽  
Underlying Theory ◽  
Hydrodynamical Limit ◽  
Low Energies

Bulk viscosity is an important transport coefficient that exists in the hydrodynamical limit only when the underlying theory is non-conformal. One example being thermal QCD with large number of colors. We study bulk viscosity in such a theory at low energies and at weak and strong ’t Hooft couplings when the temperature is above the deconfinement temperature. The weak coupling analysis is based on Boltzmann equation from kinetic theory whereas the strong coupling analysis uses non-conformal holographic techniques from string and M-theories. Using these, many properties associated with bulk viscosity may be explicitly derived.

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