scholarly journals THE PROPER TIME FORMALISM, GAUGE INVARIANCE AND THE EFFECTS OF A FINITE WORLD SHEET CUTOFF IN STRING THEORY

1995 ◽  
Vol 10 (31) ◽  
pp. 4501-4519 ◽  
Author(s):  
B. SATHIAPALAN
Keyword(s):  
Gauge Transformation ◽  
Gauge Invariance ◽  
Proper Time ◽  
World Sheet ◽  
Massive Mode ◽  
Yang Mills ◽  
Previous Discussion ◽  
Time Formalism ◽  
Klein Gordon ◽  
Type Interaction

We discuss the issue of going off-shell in the proper time formalism. This is done by keeping a finite world sheet cutoff. We construct one example of an off-shell covariant Klein-Gordon type interaction. For a suitable choice of the gauge transformation of the scalar field, gauge invariance is maintained off-mass-shell. However, at the second order in the gauge field interaction, one finds that [U(1)] gauge invariance is violated due to the finite cutoff. Interestingly, we find, to the lowest order, that by adding a massive mode with appropriate gauge transformation laws to the sigma model background, we can restore gauge invariance. The gauge transformation law is found to be consistent, to the order calculated, with what one expects from the interacting equation of motion of the massive field. We also extend some previous discussion on applying the proper time formalism for propagating gauge particles, to the interacting (i.e. Yang-Mills) case.

scholarly journals PROPER TIME FORMALISM AND GAUGE INVARIANCE IN OPEN STRING INTERACTIONS

1994 ◽  
Vol 09 (18) ◽  
pp. 1681-1693
Author(s):  
B. SATHIAPALAN
Keyword(s):  
Sigma Model ◽  
Gordon Equation ◽  
Proper Time ◽  
Open String ◽  
Gauge Invariant ◽  
Point Particles ◽  
Boundary Terms ◽  
Time Formalism ◽  
Klein Gordon ◽  
Model Formalism

The issue of gauge invariances in the sigma model formalism is discussed at the free and interacting level. The problem of deriving gauge invariant interacting equations can be addressed using the proper time formalism. This formalism is discussed, both for point particles and strings. The covariant Klein-Gordon equation arises in a geometric way from the boundary terms. This formalism is similar to the background independent open string formalism introduced by Witten.

scholarly journals ON COVARIANT DERIVATIVES AND GAUGE INVARIANCE IN THE PROPER TIME FORMALISM FOR STRING THEORY

1996 ◽  
Vol 11 (04) ◽  
pp. 317-329 ◽  
Author(s):  
B. SATHIAPALAN
Keyword(s):  
Gauge Field ◽  
Gauge Invariance ◽  
Covariant Derivative ◽  
Proper Time ◽  
Gauge Fields ◽  
Minimal Coupling ◽  
Covariant Derivatives ◽  
Time Formalism ◽  
Free Level ◽  
Higher Spin

It is shown that the idea of “minimal” coupling to gauge fields can be conveniently implemented in the proper time formalism by identifying the equivalent of a “covariant derivative”. This captures some of the geometric notion of the gauge field as a connection. The proper time equation is also generalized so that the gauge invariances associated with higher spin massive modes can be made manifest, at the free level, using loop variables. Some explicit examples are worked out illustrating these ideas.

scholarly journals Renormalization group flow for SU(2) Yang-Mills theory and gauge invariance

1994 ◽  
Vol 421 (2) ◽  
pp. 429-455 ◽  
Author(s):  
M. Bonini ◽  
M. D'Attanasio ◽  
G. Marchesini
Keyword(s):  
Renormalization Group ◽  
Gauge Invariance ◽  
Renormalization Group Flow ◽  
Yang Mills ◽  
Group Flow

scholarly journals EXTENSION OF THE POINCARÉ GROUP AND NON-ABELIAN TENSOR GAUGE FIELDS

2010 ◽  
Vol 25 (31) ◽  
pp. 5765-5785 ◽  
Author(s):  
GEORGE SAVVIDY
Keyword(s):  
Gauge Group ◽  
Gauge Transformation ◽  
Space Time ◽  
Gauge Fields ◽  
Poincaré Group ◽  
Matrix Representations ◽  
Poincare Group ◽  
Yang Mills ◽  
The Matrix ◽  
Transversal Plane

In the recently proposed generalization of the Yang–Mills theory, the group of gauge transformation gets essentially enlarged. This enlargement involves a mixture of the internal and space–time symmetries. The resulting group is an extension of the Poincaré group with infinitely many generators which carry internal and space–time indices. The matrix representations of the extended Poincaré generators are expressible in terms of Pauli–Lubanski vector in one case and in terms of its invariant derivative in another. In the later case the generators of the gauge group are transversal to the momentum and are projecting the non-Abelian tensor gauge fields into the transversal plane, keeping only their positively definite spacelike components.

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.

scholarly journals Absorption Cross Section and Decay Rate of Dilatonic Black Strings

2018 ◽  
Vol 2018 ◽  
pp. 1-7 ◽  
Author(s):  
Huriye Gürsel ◽  
İzzet Sakallı
Keyword(s):  
Scalar Field ◽  
Decay Rate ◽  
Cross Section ◽  
Absorption Cross Section ◽  
Gordon Equation ◽  
Absorption Cross ◽  
Black String ◽  
Yang Mills ◽  
Klein Gordon ◽  
Analytical Expressions

We studied in detail the propagation of a massive tachyonic scalar field in the background of a five-dimensional (5D) Einstein–Yang–Mills–Born–Infeld–dilaton black string: the massive Klein–Gordon equation was solved, exactly. Next we obtained complete analytical expressions for the greybody factor, absorption cross section, and decay rate for the tachyonic scalar field in the geometry under consideration. The behaviors of the obtained results are graphically represented for different values of the theory’s free parameters. We also discuss why tachyons should be used instead of ordinary particles for the analytical derivation of the greybody factor of the dilatonic 5D black string.

scholarly journals The large proper-time expansion of Yang-Mills plasma as a resurgent transseries

2019 ◽  
Vol 2019 (2) ◽  
Author(s):  
Inês Aniceto ◽  
Jakub Jankowski ◽  
Ben Meiring ◽  
Michał Spaliński
Keyword(s):  
Proper Time ◽  
Yang Mills ◽  
Time Expansion

Evaluation of loop diagrams using quantum mechanics

1992 ◽  
Vol 70 (8) ◽  
pp. 652-655 ◽  
Author(s):  
D. G. C. McKeon
Keyword(s):  
Field Theory ◽  
Quantum Mechanics ◽  
Matrix Element ◽  
Proper Time ◽  
Quantum Field ◽  
Loop Momentum ◽  
Loop Order ◽  
Point Function ◽  
Integral Formalism ◽  
Time Formalism

In using the proper time formalism, Schwinger demonstrated that one-loop processes in quantum field theory can be expressed in terms of a matrix element whose form is encountered in quantum mechanics, and which can be evaluated using the Heisenberg formalism. We demonstrate how instead this matrix element can be computed using standard results in the path-integral formalism. The technique of operator regularization allows one to extend this approach to arbitrary loop order. No loop-momentum integrals are ever encountered. This technique is illustrated by computing the two-point function in [Formula: see text] theory to one-loop order.

Quadratic Lagrangians and gauge-invariance in covariant field theories

1960 ◽  
Vol 56 (3) ◽  
pp. 247-251 ◽  
Author(s):  
G. Stephenson
Keyword(s):  
General Relativity ◽  
Gauge Transformation ◽  
Gauge Invariance ◽  
Variational Principles ◽  
Scalar Function ◽  
Field Equations ◽  
General Group ◽  
Metric Tensor ◽  
Invariance Properties ◽  
Image Position

The idea of gauge-invariance in general relativity was first introduced by Weyl(1) who proposed that the field equations of gravitation should be invariant, not only under the general group of coordinate transformations, but also under the gauge-transformationwhere is the symmetric metric tensor, is the symmetric affine connexion and λ(x8) is an arbitrary scalar function of the coordinates. In this way it was possible to introduce into the theory a four-vector Ak which in consequence of (1·1) transformed assuch that the six-vector remained an invariant quantity under the gauge-transformation. It was Weyl's hope that by widening the invariance properties gauge-transformation. It was Weyl's hope that by widening the invariance properties of general relativity in this way the vector Ak and its associated six-vector Fik could be interpreted as representing the electromagnetic field. However, no obvious or unique way of doing this was found. More recently (see Stephenson (2,3) and Higgs (4)) gaugeinvariant variational principles formed from Lagrangians quadratic in the Riemann—Christoffel curvature tensor and its contractions have been discussed by performing the variations with respect to the symetric and symetric independently (following the palatini method).

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