scholarly journals Gauge invariant derivative expansion of the effective action at finite temperature and density and the scalar field in2+1dimensions

2001 ◽  
Vol 63 (4) ◽  
Author(s):  
C. García-Recio ◽  
L. L. Salcedo
Keyword(s):  
Scalar Field ◽  
Effective Action ◽  
Finite Temperature ◽  
Derivative Expansion ◽  
Gauge Invariant

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 The fermionic universal one-loop effective action

2020 ◽  
Vol 2020 (11) ◽  
Author(s):  
Sebastian A. R. Ellis ◽  
Jérémie Quevillon ◽  
Pham Ngoc Hoa Vuong ◽  
Tevong You ◽  
Zhengkang Zhang
Keyword(s):  
Path Integral ◽  
Effective Action ◽  
Covariant Derivative ◽  
Heavy Fermion ◽  
Axial Vector ◽  
Derivative Expansion ◽  
Universal Structure ◽  
Pseudo Scalar ◽  
Matching Techniques ◽  
Analytical Expressions

Abstract Recent development of path integral matching techniques based on the covariant derivative expansion has made manifest a universal structure of one-loop effective Lagrangians. The universal terms can be computed once and for all to serve as a reference for one-loop matching calculations and to ease their automation. Here we present the fermionic universal one-loop effective action (UOLEA), resulting from integrating out heavy fermions (Dirac or Majorana) with scalar, pseudo-scalar, vector and axial-vector couplings. We also clarify the relation of the new terms computed here to terms previously computed in the literature and those that remain to complete the UOLEA. Our results can be readily used to efficiently obtain analytical expressions for effective operators arising from heavy fermion loops [13].

scholarly journals Effective action for a quantum scalar field in warped spaces

2015 ◽  
Vol 75 (11) ◽  
Author(s):  
J. M. Hoff da Silva ◽  
E. L. Mendonça ◽  
E. Scatena
Keyword(s):  
Scalar Field ◽  
Effective Action

scholarly journals Form factor decompositions of the QCD four - gluon vertex

2018 ◽  
Vol 182 ◽  
pp. 02114 ◽  
Author(s):  
Naser Ahmadiniaz ◽  
Christian Schubert
Keyword(s):  
Field Theory ◽  
Form Factor ◽  
Effective Action ◽  
The Other ◽  
Integration By Parts ◽  
Ward Identities ◽  
Gauge Invariant ◽  
Gluon Vertex ◽  
Invariant Structures ◽  
String Amplitudes

The Bern-Kosower formalism, originally developed around 1990 as a novel way of obtaining on-shell amplitudes in field theory as limits of string amplitudes, has recently been shown to be extremely effcient as a tool for obtaining form factor decompositions of the N - gluon vertices. Its main advantages are that gauge invariant structures can be generated by certain systematic integration-by-parts procedures, making unnecessary the usual tedious analysis of the non-abelian off-shell Ward identities, and that the scalar, spinor and gluon loop cases can be treated in a unified way. After discussing the method in general for the N - gluon case, I will show in detail how to rederive the Ball- Chiu decomposition of the three - gluon vertex, and finally present two slightly different decompositions of the four - gluon vertex, one generalizing the Ball Chiu one, the other one closely linked to the QCD effective action.

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