scholarly journals TWO-LOOP VACUUM DIAGRAMS IN BACKGROUND FIELD AND THE HEISENBERG–EULER EFFECTIVE ACTION

2008 ◽  
Vol 23 (32) ◽  
pp. 5201-5215 ◽  
Author(s):  
MAREK KRASŇANSKÝ
Keyword(s):  
Explicit Form ◽  
Effective Action ◽  
Background Field ◽  
Two Dimensions ◽  
Recursion Relations ◽  
Four Dimensions ◽  
Self Duality

We show that in arbitrary even dimensions, the two-loop scalar QED Heisenberg–Euler effective action can be reduced to simple one-loop quantities, using just algebraic manipulations, when the constant background field satisfies F2 = -f2𝟙, which in four dimensions coincides with the condition for self-duality, or definite helicity. This result relies on new recursion relations between two-loop and one-loop diagrams, with background field propagators. It also yields an explicit form of the renormalized two-loop effective action in a general constant background field in two dimensions.

scholarly journals SELF-DUALITY AND THE KdV HIERARCHY

1993 ◽  
Vol 08 (07) ◽  
pp. 661-665
Author(s):  
ASHOK DAS ◽  
C.A.P. GALVĀO
Keyword(s):  
The Self ◽  
Gauge Fields ◽  
Recursion Relations ◽  
Four Dimensions ◽  
Kdv Hierarchy ◽  
Self Duality ◽  
Duality Condition

We derive the entire KdV hierarchy as well as the recursion relations from the self-duality condition on gauge fields in four dimensions.

Impact of Job Stress and Social Support on Job Satisfaction among Academic Staff

2016 ◽  
Vol 7 (1) ◽  
Author(s):  
Kumari Kumkum ◽  
R. N. Singh ◽  
Yogershi Rajpoot
Keyword(s):  
Social Support ◽  
Job Satisfaction ◽  
Job Stress ◽  
Positive Impact ◽  
Academic Staff ◽  
Two Dimensions ◽  
The Other ◽  
Human Beings ◽  
Negative Consequences ◽  
Four Dimensions

There may be so many negative consequences of stress for human beings and dissatisfaction among employees happens to be one of the major problems. It indicates negative feelings that individuals have regarding their jobs or its facets. On the other hand, social support is assumed to be mitigating the relationship between negative aspects of the work environment and job satisfaction. Job stress is said to be associated with job dissatisfaction as well as experience of strain. In view of the above, this study examined the role of job stress and social support in job satisfaction. The sample consisted of 30 school teachers from different school of Varanasi (U.P.). The job stress, job satisfaction and social support scales were administered on the participants. The responses of the participants were converted into scores for statistical analyses. The scores of participants on the scales were correlated. The findings revealed that job stress led to increased job satisfaction. It is against the proposed hypothesis and it appears as if the social support received by the participants is a factor behind it. Two of the four dimensions of social support were found to exert positive impact on job satisfaction but the other two dimensions were not found to be correlated with it. The findings are thoroughly discussed and interpreted.

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.

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 Derivative corrections to the Heisenberg-Euler effective action

2021 ◽  
Vol 2021 (9) ◽  
Author(s):  
Felix Karbstein
Keyword(s):  
Electric Fields ◽  
Effective Action ◽  
Vacuum Polarization ◽  
Strong Field ◽  
Background Field ◽  
Polarization Tensor ◽  
Quantum Vacuum ◽  
Electron Positron ◽  
Vacuum Polarization Tensor ◽  
Electron Positron Pair

Abstract We show that the leading derivative corrections to the Heisenberg-Euler effective action can be determined efficiently from the vacuum polarization tensor evaluated in a homogeneous constant background field. After deriving the explicit parameter-integral representation for the leading derivative corrections in generic electromagnetic fields at one loop, we specialize to the cases of magnetic- and electric-like field configurations characterized by the vanishing of one of the secular invariants of the electromagnetic field. In these cases, closed-form results and the associated all-orders weak- and strong-field expansions can be worked out. One immediate application is the leading derivative correction to the renowned Schwinger-formula describing the decay of the quantum vacuum via electron-positron pair production in slowly-varying electric fields.

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.

Degenerate classical minima and instantons

2021 ◽  
pp. 942-959
Author(s):  
Jean Zinn-Justin
Keyword(s):  
Field Theory ◽  
Ground State ◽  
Stochastic Dynamics ◽  
Minimum Energy ◽  
Two Dimensions ◽  
Quantum Theories ◽  
Four Dimensions ◽  
Quantum Tunnelling ◽  
Charge Conjugation Parity ◽  
Double Well Potential

Instantons play an important role in the following situation: quantum theories corresponding to classical actions that have non-continuously connected degenerate minima. The simplest examples are provided by one-dimensional quantum systems with symmetries and potentials with non-symmetric minima. Classically, the states of minimum energy correspond to a particle sitting at any of the minima of the potential. The position of the particle breaks (spontaneously) the symmetry of the system. By contrast, in quantum mechanics (QM), the modulus of the ground-state wave function is large near all the minima of the potential, as a consequence of barrier penetration effects. Two typical examples illustrate this phenomenon: the double-well potential, and the cosine potential, whose periodic structure is closer to field theory examples. In the context of stochastic dynamics, instantons are related to Arrhenius law. The proof of the existence of instantons relies on an inequality related to supersymmetric structures, and which generalizes to some field theory examples. Again, the presence of instantons again indicates that the classical minima are connected by quantum tunnelling, and that the symmetry between them is not spontaneously broken. Examples of such a situation are provided, in two dimensions, by the charge conjugation parity (CP) (N − 1) models and, in four dimensions, by SU(2) gauge theories.

scholarly journals The Service Quality Dimensions that Affect Customer Satisfaction in the Jordanian Banking Sector

2019 ◽  
Vol 11 (4) ◽  
pp. 1113 ◽  
Author(s):  
Miklós Pakurár ◽  
Hossam Haddad ◽  
János Nagy ◽  
József Popp ◽  
Judit Oláh
Keyword(s):  
Customer Satisfaction ◽  
Service Quality ◽  
Banking Sector ◽  
Two Dimensions ◽  
Initial Model ◽  
Four Dimensions ◽  
Sample Data ◽  
Quality Dimensions ◽  
Service Quality Dimensions ◽  
Financial Aspect

Banks must meet the needs of their customers in order to achieve sustainable development. The aim of this paper is to examine service quality dimensions, by using the modified SERVQUAL model, which can be used to measure customer satisfaction, and the effect of these dimensions (tangibles, responsiveness, empathy, assurance, reliability, access, financial aspect, and employee competences) on customer satisfaction in Jordanian banks. Data were gathered from 825 customers in the Jordanian banking sector. The sample data were statistically analyzed through exploratory factor analysis by the SPSS program to determine service quality perception and customer satisfaction. The results illustrate that the modified SERVQUAL Model extracted four subscales in the new model instead of eight in the initial model. The first subscale contains four dimensions—assurance, reliability, access and employee competences. The second subscale consists of two dimensions—responsiveness and empathy. The third and fourth subscales—financial aspect and tangibility—are separate factors. Further studies should consider the dimensions of access, financial aspect, and employee competences as essential parts of service quality dimensions with the other subscales, so as to improve wider customer satisfaction in the banking sector. In the authors’ opinion, the modified SERVQUAL model is useful for addressing customer satisfaction in the banking sector.

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