scholarly journals On plasmon contribution to the hot A0 condensate

2019 ◽  
Vol 27 (2) ◽  
pp. 3-8
Author(s):  
O. A. Borisenko ◽  
V. V. Skalozub
Keyword(s):  
Effective Action ◽  
Field Component ◽  
Background Field ◽  
Internal Space ◽  
Long Distance ◽  
Standard Definition ◽  
Temporal Gauge ◽  
Condensation Phenomenon ◽  
The One ◽  
Correlation Corrections

In SU(2) gluodynamics, the Debye gluon contribution WD(A0) to the effective action of the temporal gauge field component (we consider A0 = const) in the background Rξext is calculated at high temperaturegauge. It is shown that at A0 ≠ 0 the standard definition k0 = 0 , |k| → 0 corresponds to long distance correlations for the longitudinal in internal space gluons. The transversal gluons become screened by the A0  background field. Therefore, they give zero contributions and have to be excluded from the correlation corrections. The total effective action accounting for the one-loop, two-loop, and correct WD(A0) satisfies Nielsen’s identity that proves gauge invariance of the A0 condensation phenomenon.

scholarly journals Nonperturbative one-loop effective action for QED with Yukawa couplings

2018 ◽  
Vol 33 (27) ◽  
pp. 1850157 ◽  
Author(s):  
Theodore N. Jacobson ◽  
Tonnis ter Veldhuis
Keyword(s):  
Effective Action ◽  
Proper Time ◽  
Background Field ◽  
Field Approximation ◽  
Chiral Anomaly ◽  
Dirac Fermion ◽  
Yukawa Couplings ◽  
Time Formalism ◽  
The One ◽  
The Relationship

We derive the one-loop effective action for scalar, pseudoscalar, and electromagnetic fields coupled to a Dirac fermion in an extension of QED with Yukawa couplings. Using the Schwinger proper-time formalism and zeta-function regularization, we calculate the full nonperturbative effective action to one loop in the constant background field approximation. Our result is nonperturbative in the external fields, and goes beyond existing results in the literature which treat only the first nontrivial order involving the pseudoscalar. The result has an even and odd part, which are related to the modulus and phase of the fermion functional determinant. The even contribution to the effective action involves the modulus of the effective Yukawa couplings and is invariant under global chiral transformations while the odd contribution is proportional to the angle between the scalar and pseudoscalar couplings. In different limits the effective action reduces either to the Euler–Heisenberg effective action or the Coleman–Weinberg potential. We also comment on the relationship between the odd part of the effective action and the chiral anomaly in QED.

CONVERGENCE OF DERIVATIVE AND INVERSE EFFECTIVE MASS EXPANSIONS FOR THE ONE LOOP EFFECTIVE ACTION

1987 ◽  
Vol 02 (05) ◽  
pp. 353-358 ◽  
Author(s):  
ROBERT J. PERRY ◽  
MING LI
Keyword(s):  
Effective Mass ◽  
Effective Action ◽  
Asymptotic Series ◽  
Background Field ◽  
Higher Order ◽  
Numerical Results ◽  
Derivative Expansion ◽  
Loop Correction ◽  
The One ◽  
Higher Order Corrections

Numerical results for the one loop correction to (ϕ4)2 are compared to results obtained from a derivative expansion and an expansion in inverse powers of the effective mass. We vary the scalar background field to illustrate when and why these expansions succeed, and how they break down. It is shown that both expansions behave like asymptotic series, with the approximation improving until higher order corrections grow in magnitude.

scholarly journals Background independent exact renormalisation

2021 ◽  
Vol 81 (2) ◽  
Author(s):  
Kevin Falls
Keyword(s):  
Path Integral ◽  
Effective Action ◽  
Beta Function ◽  
Background Field ◽  
Flow Equation ◽  
Renormalisation Group ◽  
Gauge Invariant ◽  
Yang Mills ◽  
The One ◽  
Group Flow

AbstractA geometric formulation of Wilson’s exact renormalisation group is presented based on a gauge invariant ultraviolet regularisation scheme without the introduction of a background field. This allows for a manifestly background independent approach to quantum gravity and gauge theories in the continuum. The regularisation is a geometric variant of Slavnov’s scheme consisting of a modified action, which suppresses high momentum modes, supplemented by Pauli–Villars determinants in the path integral measure. An exact renormalisation group flow equation for the Wilsonian effective action is derived by requiring that the path integral is invariant under a change in the cutoff scale while preserving quasi-locality. The renormalisation group flow is defined directly on the space of gauge invariant actions without the need to fix the gauge. We show that the one-loop beta function in Yang–Mills and the one-loop divergencies of General Relativity can be calculated without fixing the gauge. As a first non-perturbative application we find the form of the Yang–Mills beta function within a simple truncation of the Wilsonian effective action.

scholarly journals Harmonic Superspace Approach to the Effective Action in Six-Dimensional Supersymmetric Gauge Theories

Symmetry ◽  
2019 ◽  
Vol 11 (1) ◽  
pp. 68 ◽  
Author(s):  
Ioseph Buchbinder ◽  
Evgeny Ivanov ◽  
Boris Merzlikin ◽  
Konstantin Stepanyantz
Keyword(s):  
Effective Action ◽  
Gauge Theories ◽  
Proper Time ◽  
Background Field ◽  
Field Method ◽  
Quantum Corrections ◽  
Supersymmetric Gauge Theories ◽  
Loop Approximation ◽  
Supersymmetric Gauge ◽  
The One

We review the recent progress in studying the quantum structure of 6 D , N = ( 1 , 0 ) , and N = ( 1 , 1 ) supersymmetric gauge theories formulated through unconstrained harmonic superfields. The harmonic superfield approach allows one to carry out the quantization and calculations of the quantum corrections in a manifestly N = ( 1 , 0 ) supersymmetric way. The quantum effective action is constructed with the help of the background field method that secures the manifest gauge invariance of the results. Although the theories under consideration are not renormalizable, the extended supersymmetry essentially improves the ultraviolet behavior of the lowest-order loops. The N = ( 1 , 1 ) supersymmetric Yang–Mills theory turns out to be finite in the one-loop approximation in the minimal gauge. Furthermore, some two-loop divergences are shown to be absent in this theory. Analysis of the divergences is performed both in terms of harmonic supergraphs and by the manifestly gauge covariant superfield proper-time method. The finite one-loop leading low-energy effective action is calculated and analyzed. Furthermore, in the Abelian case, we discuss the gauge dependence of the quantum corrections and present its precise form for the one-loop divergent part of the effective action.

scholarly journals THE EFFECTIVE ACTION AND EQUATIONS OF MOTION OF CURVED LOCAL AND GLOBAL VORTICES: ROLE OF THE FIELD EXCITATIONS

2010 ◽  
Vol 24 (05) ◽  
pp. 605-628 ◽  
Author(s):  
A. A. KOZHEVNIKOV
Keyword(s):  
Scalar Field ◽  
Gauge Field ◽  
Effective Action ◽  
Equations Of Motion ◽  
Background Field ◽  
Magnetic Vortex ◽  
Goldstone Mode ◽  
Derivative Expansion ◽  
Long Distance

The effective actions for both local and global curved vortices are derived based on the derivative expansion of the corresponding field theoretic actions of the nonrelativistic Abelian Higgs and Goldstone models. The role of excitations of the modulus and the phase of the scalar field and of the gauge field (the Bogolyubov-Anderson mode) emitted and reabsorbed by vortices is elucidated. In the case of the local (gauge) magnetic vortex, they are necessary for cancellation of the long distance divergence when using the transverse form of the electric gauge field strength of the background field. In the case of global vortex taking them into account results in the Greiter–Wilczek–Witten form of the effective action for the Goldstone mode. The expressions for transverse Magnus-like force and the vortex effective mass for both local and global vortices are found. The equations of motion of both type of vortices including the terms due to the field excitations are obtained and solved in cases of large and small contour displacements.

scholarly journals COMMENTS ON THE BACKGROUND FIELD METHOD IN HARMONIC SUPERSPACE: NON-HOLOMORPHIC CORRECTIONS IN N=4 SYM

1998 ◽  
Vol 13 (20) ◽  
pp. 1623-1635 ◽  
Author(s):  
IOSEPH L. BUCHBINDER ◽  
SERGEI M. KUZENKO
Keyword(s):  
Effective Action ◽  
Background Field ◽  
Field Method ◽  
Vector Multiplet ◽  
Harmonic Superspace ◽  
Background Field Method ◽  
Field Formalism ◽  
The One

We analyze the one-loop effective action of N=4 SYM theory in the framework of the bakground field formalism in N=2 harmonic superspace. For the case of onshell background N=2 vector multiplet we prove that the effective action is free of harmonic singularities. When the lowest N=1 superspace component of the N=2 vector multiplet is switched off, the effective action of N=4 SYM theory is shown to coincide with obtained by Grisaru et al. on the base of the N=1 background field method. We compute the leading non-holomorphic corrections to the N=4 SU (2) SYM effective action.

scholarly journals INDUCED B∧F TERM AND PHOTON MASS GENERATION IN 3+1 DIMENSIONS

1994 ◽  
Vol 09 (27) ◽  
pp. 4717-4726 ◽  
Author(s):  
M. LEBLANC ◽  
R. MACKENZIE ◽  
P.K. PANIGRAHI ◽  
R. RAY
Keyword(s):  
Effective Action ◽  
Higgs Mechanism ◽  
Photon Mass ◽  
Dimensional Model ◽  
Field Mass ◽  
Long Distance ◽  
Mass Generation ◽  
Abelian Gauge ◽  
Gap Equation ◽  
The One

Analyzing a (3+1)-dimensional model with four-fermi interactions, we show that topological B∧F terms (both Abelian and non-Abelian) can be induced radiatively by massive fermions at the one-loop level. It is further pointed out that a mechanism of photon (or non-Abelian gauge field) mass generation distinct from the usual Higgs mechanism, through the B∧F term, is also implemented in the long distance effective action of this model, provided a gap equation is satisfied.

Infrared finiteness of the two-loop correction to the Chern–Simons term in the Yang–Mills–Chern–Simons theory

1995 ◽  
Vol 73 (5-6) ◽  
pp. 344-348 ◽  
Author(s):  
Yeong-Chuan Kao ◽  
Hsiang-Nan Li
Keyword(s):  
Effective Action ◽  
Background Field ◽  
Landau Gauge ◽  
Quantum Corrections ◽  
Simons Theory ◽  
Loop Correction ◽  
Loop Contribution ◽  
Yang Mills ◽  
Chern Simons ◽  
Chern Simons Theory

We show that the two-loop contribution to the coefficient of the Chern–Simons term in the effective action of the Yang–Mills–Chern–Simons theory is infrared finite in the background field Landau gauge. We also discuss the difficulties in verifying the conjecture, due to topological considerations, that there are no more quantum corrections to the Chern–Simons term other than the well-known one-loop shift of the coefficient.

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.

Sign in / Sign up

Export Citation Format

Share Document