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 COMPLETE CLASSES OF GUTS WITH VANISHING ONE-LOOP BETA FUNCTIONS

1994 ◽  
Vol 09 (29) ◽  
pp. 5053-5075
Author(s):  
WOLFGANG LUCHA ◽  
FRANZ F. SCHÖBERL
Keyword(s):  
Gauge Coupling ◽  
Coupling Constants ◽  
Coupling Constant ◽  
Finiteness Conditions ◽  
Grand Unified Theories ◽  
Unified Theories ◽  
Dimensionless Coupling ◽  
The One ◽  
The Masses ◽  
Gauge Coupling Constant

By explicit solution of the one-loop finiteness conditions for all dimensionless coupling constants (i.e. the gauge coupling constant as well as Yukawa and quartic scalar-boson self-interaction coupling constants), two classes of grand unified theories characterized by renormalization-group beta functions which all vanish at least at the one-loop level are constructed and analyzed with respect to the (suspected) appearance of quadratic divergences, with the result that without exception in all of these models the masses of both vector and scalar bosons receive quadratically divergent one-loop contributions.

scholarly journals Dynamics and the emergence of geometry in an information mesh

2020 ◽  
Vol 80 (8) ◽  
Author(s):  
Philip Tee
Keyword(s):  
Ground State ◽  
Quantum Particle ◽  
Coupling Constants ◽  
Coupling Constant ◽  
Graph Properties ◽  
Graph Theoretical Approach ◽  
Dimensionless Coupling ◽  
Dimensionless Coupling Constant ◽  
Ground State Geometry ◽  
The Continuum

Abstract The idea of a graph theoretical approach to modeling the emergence of a quantized geometry and consequently spacetime, has been proposed previously, but not well studied. In most approaches the focus has been upon how to generate a spacetime that possesses properties that would be desirable at the continuum limit, and the question of how to model matter and its dynamics has not been directly addressed. Recent advances in network science have yielded new approaches to the mechanism by which spacetime can emerge as the ground state of a simple Hamiltonian, based upon a multi-dimensional Ising model with one dimensionless coupling constant. Extensions to this model have been proposed that improve the ground state geometry, but they require additional coupling constants. In this paper we conduct an extensive exploration of the graph properties of the ground states of these models, and a simplification requiring only one coupling constant. We demonstrate that the simplification is effective at producing an acceptable ground state. Moreover we propose a scheme for the inclusion of matter and dynamics as excitations above the ground state of the simplified Hamiltonian. Intriguingly, enforcing locality has the consequence of reproducing the free non-relativistic dynamics of a quantum particle.

scholarly journals HOLOMORPHIC EFFECTIVE ACTION OF N=2 SYM THEORY FROM HARMONIC SUPERSPACE WITH CENTRAL CHARGES

2000 ◽  
Vol 15 (30) ◽  
pp. 1859-1877 ◽  
Author(s):  
S. EREMIN ◽  
E. IVANOV
Keyword(s):  
Effective Action ◽  
Coupled System ◽  
Adjoint Representation ◽  
Coulomb Branch ◽  
Harmonic Superspace ◽  
The One ◽  
Diagram Techniques

We compute the one-loop holomorphic effective action of the massless Cartan sector of N=2 SYM theory in the Coulomb branch, taking into account the contributions both from the charged hypermultiplets and off-diagonal components of the gauge superfield. We use the manifestly supersymmetric harmonic superfields diagram techniques adapted to N=2 supersymmetry with the central charges induced by Cartan generators. The (anti)holomorphic part proves to be proportional to the central charges and it has the generic form of Seiberg's action obtained by integrating U (1)R anomaly. It vanishes for N=4 SYM theory, i.e. the coupled system of N=2 gauge superfield and hypermultiplet in the adjoint representation.

scholarly journals Energy-momentum of the Friedmann models in General Relativity and the teleparallel theory of gravity

2008 ◽  
Vol 86 (11) ◽  
pp. 1297-1302 ◽  
Author(s):  
M Sharif ◽  
M Jamil Amir
Keyword(s):  
General Relativity ◽  
Energy Density ◽  
Spherical Shell ◽  
Momentum Density ◽  
Friedmann Universe ◽  
Coupling Constant ◽  
Dimensionless Coupling ◽  
Teleparallel Theory ◽  
Theory Of Gravity ◽  
Dimensionless Coupling Constant

This paper is devoted to the evaluation of the energy-momentum density components for the Friedmann models. For this purpose, we have used Møller’s pseudotensor prescription in General Relativity and a certain energy-momentum density developed from Møller’s teleparallel formulation. We show that the energy density of the closed Friedmann universe vanishes on the spherical shell at the radius ρ = 2[Formula: see text]. This coincides with the earlier results available in the literature. We also discuss the energy of the flat and open models. A comparison shows a partial consistency between Møller’s pseudotensor for General Relativity and teleparallel theory. Further, we show that the results are independent of the free dimensionless coupling constant of the teleparallel gravity.PACS No.: 04.20.–q

Vacuum effects in a spatially homogeneous and isotropic cosmological background

1992 ◽  
Vol 70 (2-3) ◽  
pp. 143-147
Author(s):  
Victor M. Villalba ◽  
Umberto Percoco
Keyword(s):  
Separation Of Variables ◽  
Particle Creation ◽  
Coupling Constant ◽  
Positive Cosmological Constant ◽  
Dirac Equations ◽  
Klein Gordon ◽  
Dimensionless Coupling ◽  
Spatially Homogeneous ◽  
Dimensionless Coupling Constant ◽  
Vacuum Effects

In this article we obtain, by separation of variables, an exact solution to the Klein–Gordon and Dirac equations in a cosmological, spatially-closed, Robertson–Walker space-time with a positive cosmological constant Λ. The model is associated with a universe filled with radiation. We analyze the phenomenon of particle creation for different values of the dimensionless coupling constant ξ.

BLACK HOLES AND SOLITONS OF THE NONLINEAR ISOVECTOR MODEL

2006 ◽  
Vol 21 (21) ◽  
pp. 4343-4354 ◽  
Author(s):  
NEMATOLLAH RIAZI ◽  
HASSAN NIAD ◽  
SEYED HOSSEIN HENDI
Keyword(s):  
Strong Coupling ◽  
Asymptotic Form ◽  
Flat Space ◽  
Strong Coupling Regime ◽  
Spherically Symmetric ◽  
Coupling Constant ◽  
Curved Space ◽  
Dimensionless Coupling ◽  
Dimensionless Coupling Constant ◽  
Black Hole Solutions

We formulate the nonlinear isovector model in a curved background and calculate the spherically symmetric solutions for weak and strong coupling regimes. The question whether gravity has appreciable effects on the structure of solitons will be examined, in the framework of the calculated solutions, by comparing the flat-space and curved-space solutions. It turns out that in the strong coupling regime, gravity has essential effects on the solutions. It is also shown that the asymptotic form of the metric conforms with that of the charged Reissner–Nordstrom metric. The dimensionless coupling constant of the model has a limit, beyond which a horizon appears in the solutions, indicating the presence of black hole solutions.

scholarly journals On the Vilkovisky-DeWitt approach and renormalization group in effective quantum gravity

2020 ◽  
Vol 2020 (10) ◽  
Author(s):  
Breno L. Giacchini ◽  
Tibério de Paula Netto ◽  
Ilya L. Shapiro
Keyword(s):  
Renormalization Group ◽  
Quantum Gravity ◽  
Effective Action ◽  
Planck Scale ◽  
Renormalization Group Flow ◽  
Higher Derivative ◽  
Gauge Fixing ◽  
Total Action ◽  
The One ◽  
Group Flow

Abstract The effective action in quantum general relativity is strongly dependent on the gauge-fixing and parametrization of the quantum metric. As a consequence, in the effective approach to quantum gravity, there is no possibility to introduce the renormalization-group framework in a consistent way. On the other hand, the version of effective action proposed by Vilkovisky and DeWitt does not depend on the gauge-fixing and parametrization off- shell, opening the way to explore the running of the cosmological and Newton constants as well as the coefficients of the higher-derivative terms of the total action. We argue that in the effective framework the one-loop beta functions for the zero-, two- and four-derivative terms can be regarded as exact, that means, free from corrections coming from the higher loops. In this perspective, the running describes the renormalization group flow between the present-day Hubble scale in the IR and the Planck scale in the UV.

scholarly journals On a structure of the one-loop divergences in 4D harmonic superspace sigma-model

2022 ◽  
Vol 82 (1) ◽  
Author(s):  
I. L. Buchbinder ◽  
A. S. Budekhina ◽  
B. S. Merzlikin
Keyword(s):  
Effective Action ◽  
Sigma Model ◽  
Proper Time ◽  
Kähler Manifold ◽  
Quantum Structure ◽  
Harmonic Superspace ◽  
Component Structure ◽  
Covariant Derivatives ◽  
The One ◽  
Quantum Splitting

AbstractWe study the quantum structure of four-dimensional $${{\mathcal {N}}}=2$$ N = 2 superfield sigma-model formulated in harmonic superspace in terms of the omega-hypermultiplet superfield $$\omega $$ ω . The model is described by harmonic superfield sigma-model metric $$g_{ab}(\omega )$$ g ab ( ω ) and two potential-like superfields $$L^{++}_{a}(\omega )$$ L a + + ( ω ) and $$L^{(+4)}(\omega )$$ L ( + 4 ) ( ω ) . In bosonic component sector this model describes some hyper-Kähler manifold. The manifestly $${{\mathcal {N}}}=2$$ N = 2 supersymmetric covariant background-quantum splitting is constructed and the superfield proper-time technique is developed to calculate the one-loop effective action. The one-loop divergences of the superfield effective action are found for arbitrary $$g_{ab}(\omega ), L^{++}_{a}(\omega ), L^{(+4)}(\omega )$$ g ab ( ω ) , L a + + ( ω ) , L ( + 4 ) ( ω ) , where some specific analogy between the algebra of covariant derivatives in the sigma-model and the corresponding algebra in the $${{\mathcal {N}}}=2$$ N = 2 SYM theory is used. The component structure of divergences in the bosonic sector is discussed.

scholarly journals Induced Maxwell–Chern–Simons effective action in very special relativity

2020 ◽  
Vol 80 (12) ◽  
Author(s):  
R. Bufalo ◽  
M. Ghasemkhani ◽  
Z. Haghgouyan ◽  
A. Soto
Keyword(s):  
Special Relativity ◽  
Effective Action ◽  
Nonlocal Effects ◽  
Dynamical Part ◽  
Topological Materials ◽  
Ohmic Behavior ◽  
Higher Derivative ◽  
Very Special Relativity ◽  
The One ◽  
Chern Simons

AbstractIn this paper, we study the one-loop induced photon’s effective action in the very special relativity electrodynamics in $$(2+1)$$ ( 2 + 1 ) spacetime ($$\hbox {VSR}$$ VSR –$$\hbox {QED}_{3}$$ QED 3 ). Due to the presence of new nonlocal couplings resulting from the VSR gauge symmetry, we have additional graphs contributing to the $$\langle AA\rangle $$ ⟨ A A ⟩ and $$\langle AAA \rangle $$ ⟨ A A A ⟩ amplitudes. From these contributions, we discuss the VSR generalization of the Abelian Maxwell–Chern–Simons Lagrangian, consisting in the dynamical part and the Chern–Simons-like self-couplings, respectively. We use the VSR–Chern–Simons electrodynamics to discuss some non-Ohmic behavior on topological materials, in particular VSR effects on Hall’s conductivity. In the dynamical part of the effective action, we observe the presence of a UV/IR mixing, due to the entanglement of the VSR nonlocal effects to the quantum higher-derivative terms. Furthermore, in the self-coupling aspect, we verify the validity of the Furry’s theorem in the $${\hbox {VSR}}$$ VSR –$$\hbox {QED}_{3}$$ QED 3 explicitly.

scholarly journals ON LOW-ENERGY EFFECTIVE ACTION OF NONCOMMUTATIVE HYPERMULTIPLET MODEL

2001 ◽  
Vol 16 (40) ◽  
pp. 2591-2603 ◽  
Author(s):  
I. B. SAMSONOV
Keyword(s):  
Effective Action ◽  
Adjoint Representation ◽  
Low Energy ◽  
Coupling Constants ◽  
Quantum Corrections ◽  
Fundamental Representation ◽  
Harmonic Superspace ◽  
Commutative Case ◽  
The One ◽  
External Gauge

We consider the noncommutative hypermultiplet model within harmonic superspace approach. The one-loop four-point contributions to the effective action of self-interacting q-hypermultiplet are computed. This model has two coupling constants instead of a single one in commutative case. It is shown that both coupling constants are generated by one-loop quantum corrections in the model of q-hypermultiplet interacting with vector multiplet. The holomorphic effective action of q-hypermultiplet in external gauge superfield is calculated. For the fundamental representation there is no uv/ir-mixing and the holomorphic potential is a ⋆-product generalization of a standard commutative one. For the adjoint representation of U(N) gauge group the leading contributions to the holomorphic effective action are given by the terms respecting for the uv/ir-mixing which are related to U(1) phase of U(N) group.

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