scholarly journals CENTRAL CHARGES AND EFFECTIVE ACTION AT FINITE TEMPERATURE AND DENSITY

2004 ◽  
Vol 19 (03) ◽  
pp. 223-238 ◽  
Author(s):  
J. GAMBOA ◽  
J. LÓPEZ-SARRIÓN ◽  
M. LOEWE ◽  
F. MÉNDEZ
Keyword(s):  
Explicit Expression ◽  
Current Algebra ◽  
Effective Action ◽  
Finite Temperature ◽  
Gauge Theories ◽  
Central Charge ◽  
Thirring Model ◽  
Coupling Constant ◽  
Four Dimensions

The current algebra for gauge theories like QCD at finite temperature and density is studied. We start considering, the massless Thirring model at finite temperature and density, finding an explicit expression for the current algebra. The central charge only depends on the coupling constant and there are not new effects due to temperature and density. From this calculation, we argue how to compute the central charge for QCD4 and we argue why the central charge in four dimensions could be modified by finite temperature and density.

THE FERMION-FERMION EFFECTIVE ACTION FOR THE THREE-DIMENSIONAL MASSIVE THIRRING MODEL

1994 ◽  
Vol 09 (18) ◽  
pp. 3143-3151 ◽  
Author(s):  
R.F. RIBEIRO ◽  
E.R. BEZERRA DE MELLO
Keyword(s):  
Schrödinger Equation ◽  
Effective Potential ◽  
Effective Action ◽  
Schrodinger Equation ◽  
Three Dimensional ◽  
Bound State ◽  
Thirring Model ◽  
Coupling Constant ◽  
Massive Thirring Model

In this paper a nonrelativistic fermion-fermion effective potential for a three-dimensional massive Thirring model is obtained in a 1/N expansion. We show, by analyzing the Schrödinger equation in the presence of this potential, that the system presents a fermion-fermion bound state for a positive value of the coupling constant g.

CONFORMAL SUPERALGEBRAS OF HIGHER SPINS

1989 ◽  
Vol 04 (24) ◽  
pp. 2363-2375 ◽  
Author(s):  
E.S. FRADKIN ◽  
V. Ya. LINETSKY
Keyword(s):  
Explicit Expression ◽  
Effective Action ◽  
Three Dimensions ◽  
Four Dimensions ◽  
Infinite Dimensional ◽  
Higher Spin ◽  
Higher Spins ◽  
Conformal Superalgebras

Infinite-dimensional conformal higher spin superalgebras are constructed. Based on the superalgebra in three dimensions, an explicit expression for the effective action is found. In four dimensions, the curvatures of higher spin conformal superalgebras are obtained.

CONSISTENT QUANTIZATION OF A CHIRAL GAUGE THEORY IN FOUR DIMENSIONS

1989 ◽  
Vol 04 (27) ◽  
pp. 2675-2683 ◽  
Author(s):  
SHOGO MIYAKE ◽  
KEN-ICHI SHIZUYA
Keyword(s):  
Gauge Theory ◽  
Gauge Symmetry ◽  
Gauge Field ◽  
Current Algebra ◽  
Gauge Theories ◽  
Present Theory ◽  
Particle Spectrum ◽  
Four Dimensions ◽  
Symmetric Formulation

Using a gauge-symmetric formulation of anomalous gauge theories, we study the consistency and symmetry contents of a chiral gauge theory in four dimensions. The gauge symmetry, restored by the inclusion of the Wess-Zumino term, is spontaneously broken and the gauge field acquires a mass. Symmetry arguments are used to determine the particle spectrum and the current algebra of the model. Our analysis indicates that, apart from a question of renormalizability, the present theory is a consistent gauge theory.

scholarly journals MASSLESS THREE-DIMENSIONAL QUANTUM ELECTRODYNAMICS AND THIRRING MODEL CONSTRAINED BY LARGE FLAVOR NUMBER

2006 ◽  
Vol 21 (18) ◽  
pp. 1451-1462
Author(s):  
A. R. FAZIO
Keyword(s):  
Finite Temperature ◽  
Quantum Electrodynamics ◽  
Degrees Of Freedom ◽  
Three Dimensional ◽  
Thirring Model ◽  
Asymptotic Freedom ◽  
Coupling Constant ◽  
Running Coupling ◽  
Running Coupling Constant ◽  
Massless Quantum

We explicitly prove that in three-dimensional massless quantum electrodynamics at finite temperature, zero density and large number of flavors, the number of infrared degrees of freedom is never larger than the corresponding number of ultraviolet. Such a result, strongly dependent on the asymptotic freedom of the theory, is reversed in three-dimensional Thirring model due to the positive derivative of its running coupling constant.

scholarly journals Effective String Description of the Confining Flux Tube at Finite Temperature

Universe ◽  
2021 ◽  
Vol 7 (6) ◽  
pp. 170
Author(s):  
Michele Caselle
Keyword(s):  
Flux Tube ◽  
Dimensional Reduction ◽  
Conformal Invariance ◽  
Finite Temperature ◽  
Gauge Theories ◽  
Linear Increase ◽  
General Introduction ◽  
Interquark Potential ◽  
Effective String Theory ◽  
Good Agreement

In this review, after a general introduction to the effective string theory (EST) description of confinement in pure gauge theories, we discuss the behaviour of EST as the temperature is increased. We show that, as the deconfinement point is approached from below, several universal features of confining gauge theories, like the ratio Tc/σ0, the linear increase of the squared width of the flux tube with the interquark distance, or the temperature dependence of the interquark potential, can be accurately predicted by the effective string. Moreover, in the vicinity of the deconfinement point the EST behaviour turns out to be in good agreement with what was predicted by conformal invariance or by dimensional reduction, thus further supporting the validity of an EST approach to confinement.

scholarly journals New bi-harmonic superspace formulation of 4D, $$ \mathcal{N} $$ = 4 SYM theory

2021 ◽  
Vol 2021 (4) ◽  
Author(s):  
I. L. Buchbinder ◽  
E. A. Ivanov ◽  
V. A. Ivanovskiy
Keyword(s):  
Effective Action ◽  
Harmonic Superspace ◽  
Four Dimensions ◽  
Yang Mills ◽  
Convenient Tool ◽  
Leading Term

Abstract We develop a novel bi-harmonic $$ \mathcal{N} $$ N = 4 superspace formulation of the $$ \mathcal{N} $$ N = 4 supersymmetric Yang-Mills theory (SYM) in four dimensions. In this approach, the $$ \mathcal{N} $$ N = 4 SYM superfield constraints are solved in terms of on-shell $$ \mathcal{N} $$ N = 2 harmonic superfields. Such an approach provides a convenient tool of constructing the manifestly $$ \mathcal{N} $$ N = 4 supersymmetric invariants and further rewriting them in $$ \mathcal{N} $$ N = 2 harmonic superspace. In particular, we present $$ \mathcal{N} $$ N = 4 superfield form of the leading term in the $$ \mathcal{N} $$ N = 4 SYM effective action which was known previously in $$ \mathcal{N} $$ N = 2 superspace formulation.

scholarly journals Supergraph calculation of one-loop divergences in higher-derivative 6D SYM theory

2020 ◽  
Vol 2020 (8) ◽  
Author(s):  
I. L. Buchbinder ◽  
E. A. Ivanov ◽  
B. S. Merzlikin ◽  
K. V. Stepanyantz
Keyword(s):  
Effective Action ◽  
A Priori ◽  
Coupling Constant ◽  
Harmonic Superspace ◽  
Classical Action ◽  
Higher Derivative ◽  
Component Approach ◽  
Dimensionless Coupling ◽  
The One ◽  
Dimensionless Coupling Constant

Abstract We apply the harmonic superspace approach for calculating the divergent part of the one-loop effective action of renormalizable 6D, $$ \mathcal{N} $$ N = (1, 0) supersymmetric higher-derivative gauge theory with a dimensionless coupling constant. Our consideration uses the background superfield method allowing to carry out the analysis of the effective action in a manifestly gauge covariant and $$ \mathcal{N} $$ N = (1, 0) supersymmetric way. We exploit the regularization by dimensional reduction, in which the divergences are absorbed into a renormalization of the coupling constant. Having the expression for the one-loop divergences, we calculate the relevant β-function. Its sign is specified by the overall sign of the classical action which in higher-derivative theories is not fixed a priori. The result agrees with the earlier calculations in the component approach. The superfield calculation is simpler and provides possibilities for various generalizations.

scholarly journals Two-loop rational terms in Yang-Mills theories

2020 ◽  
Vol 2020 (10) ◽  
Author(s):  
Jean-Nicolas Lang ◽  
Stefano Pozzorini ◽  
Hantian Zhang ◽  
Max F. Zoller
Keyword(s):  
Scattering Amplitudes ◽  
Gauge Theories ◽  
A Posteriori ◽  
Four Dimensions ◽  
Yang Mills ◽  
General Properties ◽  
Finite Set ◽  
Numerical Tools ◽  
Loop Amplitudes

Abstract Scattering amplitudes in D dimensions involve particular terms that originate from the interplay of UV poles with the (D − 4)-dimensional parts of loop numerators. Such contributions can be controlled through a finite set of process-independent rational counterterms, which make it possible to compute loop amplitudes with numerical tools that construct the loop numerators in four dimensions. Building on a recent study [1] of the general properties of two-loop rational counterterms, in this paper we investigate their dependence on the choice of renormalisation scheme. We identify a nontrivial form of scheme dependence, which originates from the interplay of mass and field renormalisation with the (D−4)-dimensional parts of loop numerators, and we show that it can be controlled through a new kind of one-loop counterterms. This guarantees that the two-loop rational counterterms for a given renormalisable theory can be derived once and for all in terms of generic renormalisation constants, which can be adapted a posteriori to any scheme. Using this approach, we present the first calculation of the full set of two-loop rational counterterms in Yang-Mills theories. The results are applicable to SU(N) and U(1) gauge theories coupled to nf fermions with arbitrary masses.

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