scholarly journals GAUGE THEORIES AS A GEOMETRICAL ISSUE OF A KALUZA–KLEIN FRAMEWORK

2005 ◽  
Vol 14 (07) ◽  
pp. 1195-1231 ◽  
Author(s):  
FRANCESCO CIANFRANI ◽  
ANDREA MARROCCO ◽  
GIOVANNI MONTANI

We present a geometrical unification theory in a Kaluza–Klein approach that achieve the geometrization of a generic gauge theory bosonic component. We show how it is possible to derive gauge charge conservation from the invariance of the model under extra-dimensional translations and to geometrize gauge connections for spinors, in order to make possible to introducing matter just through free spinorial fields. Then we present the applications to (i) a pentadimensional manifold V4 ⊗ S1 so reproducing the original Kaluza–Klein theory with some extensions related to the rule of the scalar field contained in the metric and to the introduction of matter through spinors with a phase dependance from the fifth coordinate, (ii) a seven-dimensional manifold V4 ⊗ S1 ⊗ S2, in which we geometrize the electroweak model by introducing two spinors for every leptonic family and quark generation and a scalar field with two components with opposite hypercharge responsible for spontaneous symmetry breaking.

2006 ◽  
Vol 15 (05) ◽  
pp. 717-736
Author(s):  
ORCHIDEA MARIA LECIAN ◽  
GIOVANNI MONTANI

The geometrization of the Electroweak Model is achieved in a five-dimensional Riemann–Cartan framework. Matter spinorial fields are extended to 5 dimensions by the choice of a proper dependence on the extracoordinate and of a normalization factor. U (1) weak hypercharge gauge fields are obtained from a Kaluza–Klein scheme, while the tetradic projections of the extradimensional contortion fields are interpreted as SU (2) weak isospin gauge fields. SU (2) generators are derived by the identification of the weak isospin current to the extradimensional current term in the Lagrangian density of the local Lorentz group. The geometrized U (1) and SU (2) groups will provide the proper transformation laws for bosonic and spinorial fields. Spin connections will be found to be purely Riemannian.


2020 ◽  
Vol 35 (02n03) ◽  
pp. 2040027
Author(s):  
Jean Paul Mbelek

We recall the motivation for an external scalar field, [Formula: see text], and show how it helps to improve the 5D Kaluza-Klein theory. Various applications of the theory that fit observational or experimental data in the laboratory as well as in the cosmological or astrophysical contexts are mentioned. Special attention is given to the last version of the experiment showing evidence of a torque on a torsion pendulum as predicted by the theory. New arguments that motivate extradimensions are put forward.


2005 ◽  
Vol 20 (15) ◽  
pp. 3481-3487 ◽  
Author(s):  
VLADIMIR DZHUNUSHALIEV ◽  
DOUGLAS SINGLETON ◽  
DANNY DHOKARH

In the present work we show that it is possible to arrive at a Ginzburg-Landau (GL) like equation from pure SU (2) gauge theory. This has a connection to the dual superconducting model for color confinement where color flux tubes permanently bind quarks into color neutral states. The GL Lagrangian with a spontaneous symmetry breaking potential, has such (Nielsen-Olesen) flux tube solutions. The spontaneous symmetry breaking requires a tachyonic mass for the effective scalar field. Such a tachyonic mass term is obtained from the condensation of ghost fields.


2018 ◽  
Vol 96 (5) ◽  
pp. 529-554 ◽  
Author(s):  
M.W. Kalinowski

The paper is devoted to the unification of fermions within nonsymmetric Kaluza–Klein theories. We obtain a Lagrangian for fermions in non-Abelian Kaluza–Klein theory and non-Abelian Kaluza–Klein theory with spontaneous symmetry breaking and Higgs’ mechanism. A Lagrangian for fermions for geometrized bosonic part of GSW (Glashow–Salam–Weinberg) model in our approach has been derived. Yukawa-type terms and mass terms coming from higher dimensions have been obtained. In the paper, 1/2-spin fields and 3/2-spin fields are considered.


2018 ◽  
Vol 115 (30) ◽  
pp. E6987-E6995 ◽  
Author(s):  
Snir Gazit ◽  
Fakher F. Assaad ◽  
Subir Sachdev ◽  
Ashvin Vishwanath ◽  
Chong Wang

We study a model of fermions on the square lattice at half-filling coupled to an Ising gauge theory that was recently shown in Monte Carlo simulations to exhibit Z2 topological order and massless Dirac fermion excitations. On tuning parameters, a confining phase with broken symmetry (an antiferromagnet in one choice of Hamiltonian) was also established, and the transition between these phases was found to be continuous, with coincident onset of symmetry breaking and confinement. While the confinement transition in pure gauge theories is well-understood in terms of condensing magnetic flux excitations, the same transition in the presence of gapless fermions is a challenging problem owing to the statistical interactions between fermions and the condensing flux excitations. The conventional scenario then proceeds via a two-step transition, involving a symmetry-breaking transition leading to gapped fermions followed by confinement. In contrast, here, using quantum Monte Carlo simulations, we provide further evidence for a direct, continuous transition and also find numerical evidence for an enlarged SO(5) symmetry rotating between antiferromagnetism and valence bond solid orders proximate to criticality. Guided by our numerical finding, we develop a field theory description of the direct transition involving an emergent nonabelian [SU(2)] gauge theory and a matrix Higgs field. We contrast our results with the conventional Gross–Neveu–Yukawa transition.


2015 ◽  
Vol 30 (34) ◽  
pp. 1550203 ◽  
Author(s):  
Renata Jora

We study the phase diagram of an [Formula: see text] gauge theory in terms of the number of colors [Formula: see text] and flavors [Formula: see text] with emphasis on the confinement and chiral symmetry breaking phases. We argue that as opposed to SUSY QCD there is a small region in the [Formula: see text] plane where the theory has the chiral symmetry broken but it is unconfined. The possibility of a new phase with strong confinement and chiral symmetry breaking is suggested.


1995 ◽  
Vol 10 (13) ◽  
pp. 1905-1915
Author(s):  
YOSHIAKI OHKUWA

We consider the semiclassical approximation to quantum gravity coupled with a background scalar field and a quantum matter field. We define the semiclassical time variable and write down the Schrödinger equation for the quantum matter field. This can be rewritten into the form whose time variable is the original time coordinate, when the relation of Hamilton-Jacobi holds. It is shown that the four-dimensional semiclassical time with a background scalar field is related to the five-dimensional semiclassical time without it by means of the Kaluza-Klein dimensional reduction.


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