scholarly journals Effective coupling constant of plasmons

2019 ◽  
Vol 100 (5) ◽  
Author(s):  
Margaret E. Carrington ◽  
Stanisław Mrówczyński
Keyword(s):  
Coupling Constant ◽  
Effective Coupling ◽  
Effective Coupling Constant

Critical phenomena: Corrections to scaling behaviour

2021 ◽  
pp. 421-435
Author(s):  
Jean Zinn-Justin
Keyword(s):  
Small Deviation ◽  
Critical Dimension ◽  
Coupling Constant ◽  
Effective Coupling ◽  
Corrections To Scaling ◽  
Upper Critical Dimension ◽  
Four Dimensions ◽  
Effective Coupling Constant ◽  
Scaling Behaviour ◽  
Leading Term

In preceding chapters, while deriving the scaling behaviour of correlation functions, we have always kept only the leading term in the critical region. We examine now the different corrections to the leading behaviour. For instance, when we have solved the renormalizaton group (RG) equations, so far, we have neglected the small deviation of the effective coupling constant from its fixed-point value. Moreover, to establish RG equations, we have neglected corrections subleading by powers of the cut-off, and effects of other couplings of higher canonical dimensions. Subleading terms related to the value of the effective coupling constant which give the leading corrections, at least near four dimensions, can easily be derived from the solutions of the renormalization group (RG) equations and are discussed first. The situations below and at four dimensions (the upper-critical dimension) have to be examined separately. The second type of corrections involves additional considerations and is examined in the second part of the chapter. The last section is devoted to one physics application, provided by systems with strong dipolar forces, which have 3 as upper-critical dimension.

scholarly journals T-DUALITY AND NONCOMMUTATIVE DBI ACTION

2002 ◽  
Vol 17 (04) ◽  
pp. 237-243 ◽  
Author(s):  
DAVOUD KAMANI
Keyword(s):  
Open String ◽  
Closed String ◽  
Effective Theory ◽  
Coupling Constant ◽  
Dual Theory ◽  
Effective Coupling ◽  
Effective Coupling Constant ◽  
Effective Metric

In this paper we study the noncommutative description of the DBI Lagrangian and its T-dual counterpart. We restrict the freedoms of the noncommutativity parameters of these Lagrangians. Therefore the noncommutativity parameter, the effective metric, the effective coupling constant of the string and the extra modulus [Formula: see text] of the effective T-dual theory, can be expressed in terms of the closed string variables g, B, gs and the noncommutativity parameter of the effective theory of open string.

scholarly journals THE STRONG COUPLING CONSTANT FROM HADRON STRUCTURE PHENOMENOLOGY

2012 ◽  
Vol 20 ◽  
pp. 266-273
Author(s):  
A. COURTOY ◽  
SIMONETTA LIUTI
Keyword(s):  
Perturbative Qcd ◽  
Smooth Transition ◽  
Scattering Data ◽  
Coupling Constant ◽  
Hadron Structure ◽  
Effective Coupling ◽  
Effective Coupling Constant ◽  
Running Coupling ◽  
Running Coupling Constant

We present recent developments on the role of the running coupling constant at the intersection of perturbative and nonperturbative QCD. A number of experiments show a smooth transition from small to large scales given by the four-momentum transfer in the reactions. This is at variance with perturbative QCD where the running coupling constant becomes infinite when the scale equals ΛQCD. Approaches using an effective coupling constant could help interpret the opposite trend of data as compared to standard perturbative QCD predictions. We give an overview of the role of the coupling constant in the procedure to match nonperturbative hadronic model to perturbative QCD and we propose an extraction of an effective coupling constant from inclusive electron proton scattering data at large Bjorken x.

PHASE TRANSITIONS IN ϕ4 THEORY AT FINITE DENSITIES

1989 ◽  
Vol 04 (08) ◽  
pp. 783-789 ◽  
Author(s):  
V.J. PETER ◽  
M. SABIR
Keyword(s):  
Phase Transitions ◽  
Effective Mass ◽  
Finite Temperature ◽  
Chemical Potential ◽  
Coupling Constant ◽  
Effective Coupling ◽  
Effective Coupling Constant ◽  
The One

We study the effective mass and effective coupling constant of a self interacting O(2) symmetric ϕ4 model at finite temperature and finite chemical potential in the one-loop and improved one-loop approximations. It is shown that the restored symmetry at a finite chemical potential is again broken at a higher value of chemical potential.

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