arXiv subjects

D. Singleton

Publications and source records attributed to D. Singleton.

32 records · Page 2Linked to original sources

arXiv2001

Locally Anisotropic Wormholes and Flux Tubes in 5D Gravity

In this article we examine a class of wormhole and flux tube like solutions to 5D vacuum Einstein equations. These solutions possess generic local anisotropy, and their local isotropic limit is shown to be conformally equivalent to the spherically symmetric 5D solutions of gr-qc/9807086. The anisotropic solutions investigated here have two physically distinct signatures: First, they can give rise to angular-dependent, anisotropic ``electromagnetic'' interactions. Second, they can result in a gravitational running of the ``electric'' and ``magnetic'' charges of the solutions. This gravitational running of the electromagnetic charges is linear rather than logarithmic, and could thus serve as an indirect signal for the presence of higher dimensions. The local anisotropy of these solutions is modeled using the technique of anholonomic frames with respect to which the metrics are diagonalized. If holonomic coordinates frames were used then such metrics would have off-diagonal components.

gr-qc↗

arXiv2001

Algorithmic Complexity in Cosmology and Quantum Gravity

In this article we use the idea of algorithmic complexity (AC) to study various cosmological scenarios, and as a means of quantizing the gravitational interaction. We look at 5D and 7D cosmological models where the Universe begins as a higher dimensional Planck size spacetime which fluctuates between Euclidean and Lorentzian signatures. These fluctuations are governed by the AC of the two different signatures. At some point a transition to a 4D Lorentzian signature Universe occurs, with the extra dimensions becoming ``frozen'' or non-dynamical. We also apply the idea of algorithmic complexity to study composite wormholes, the entropy of blackholes, and the path integral for quantum gravity.

gr-qc↗

arXiv2001

Non-differentiable Degrees of Freedom : Fluctuating Metric Signature

In this article we investigate the metric signature as a non-differentiable ({\it i.e.} discrete as opposed to continuous) degree of freedom. The specific model is a vacuum 7D Universe on the principal bundle with an SU(2) structural group. An analytical solution is found which to a 4D observer appears as a flat Universe with a fluctuating metric signature, and frozen extra dimensions with an SU(2) instanton gauge field. A piece of this solution with linear size of the Planck length ($\approx l_{Pl}$) can be considered as seeding the quantum birth of a regular Universe. A boundary of this piece can initiate the formation of a Lorentzian Universe filled with the gauge fields and in which the extra dimensions have been ``frozen''.

gr-qc↗

arXiv2000

Orbital and field angular momentum in the nucleon

The nucleon spin problem raises experimental and theoretical questions regarding the contribution of the orbital angular momentum of the quarks to the total spin of the nucleon. In this article we examine the commutation relationships of various operators that contribute to the total angular momentum of the nucleon. We find that the sum of the orbital plus gluon field angular momentum should satisfy the angular momentum commutators, at least up to the one-loop level. This requirement on the sum of these operators imposes a nontrivial restriction on the form of the color electric and magnetic fields. This is similar to the magnetic monopole/ electric charge system where it is only the sum of the orbital plus field angular momentum that satisfies the correct commutation relationships.

hep-ph↗

arXiv2000

Experimental test for extra dimensions in Kaluza-Klein gravity

5D Kaluza-Klein gravity has several nonasymptotically flat solutions which generally, possessed both electric and magnetic charges. In this paper we suggest that these solutions can act as quantum virtual handles (wormholes) in spacetime foam models. By applying a sufficently large, external electric and/or magnetic field it may be possible to ``inflate'' these solutions from a quantum to a classical state. This effect would lead to a possible experimental signal for higher dimensions in multidimensional gravity.

gr-qc↗

arXiv1999

Quantization of classical singular solutions in Yang-Mills theory

In this paper we apply a variant of Heisenberg's quantization method for strongly interacting, non-linear fields, to solutions of the classical Yang-Mills field equations which have bad asymptotic behavior. After quantization we find that the bad features (i.e. divergent fields and energy densities) of these solutions are moderated. From these results we argue that in general the n-point Green's functions for Yang-Mills theories can have non-perturbative pieces which can not be represented as the sum of Feynman diagrams. A formalism for dealing with these non-Feynman pieces via nonassociative field operators is suggested. These methods may also find some application in dealing with high-$T_c$ superconductors.

hep-th↗

arXiv1999

Experimental test for 5th dimension in Kaluza-Klein gravity

Several electric/magnetic charged solutions (dyons) to 5D Kaluza-Klein gravity on the principal bundle are reviewed. Here we examine the possibility that these solutions can act as quantum virtual wormholes in spacetime foam models. By applying a sufficently large, external electric and/or magnetic field it may be possible to ``inflate'' these solutions from a quantum to a classical state. This effect could lead to a possible experimental signal for higher dimensions in multidimensional gravity.

gr-qc↗

arXiv1999

Gravitational Flux Tubes

By studying multidimensional Kaluza-Klein theories, or gravity plus U(1) or SU(2) gauge fields it is shown that these theories possess similar flux tube solutions. The gauge field which fills the tube geometry of these solutions leads to a comparision with the flux tube structures in QCD. These solutions also carry a ``magnetic'' charge, Q, which for the SU(2) Einstein-Yang-Mills (EYM) system exhibits a dual relationship with the Yang-Mills gauge coupling, g, ($Q=1/g$). As $Q \to 0$ or $Q \to \infty$, $g \to \infty$ or $g \to 0$ respectively. Thus within this classical EYM field theory we find solutions which have features - flux tubes, magnetic charges, large value of the gauge coupling - that are similar to the key ingredients of confinement in QCD.

gr-qc↗

arXiv1999

Einstein-Cartan-Heisenberg Theory of Gravity with Dynamical Torsion

On the basis of an algebraic relation between torsion and a classical spinor field a new interpretation of Einstein-Cartan gravity interacting with classical spinor field is proposed. In this approach the spinor field becomes an auxiliary field and the dynamical equation for this field (the Heisenberg equation) is a dynamical, gravitational equation for torsion. The simplest version of this theory is examined where the metric degrees of freedom are frozen and only torsion plays a role. A spherically symmetric solution of this theory is examined. This solution can be interpreted, in the spirit of Wheeler's ideas of ``charge without charge'' and ``mass without mass'', as a geometrical model for an uncharged and massless particle with spin (``spin without spin'').

gr-qc↗

arXiv1999

Confining solutions of SU(3) Yang-Mills theory

Spherically and cylindrically symmetric solutions of SU(3) Yang-Mills theory are found, whose gauge potentials have confining properties. The spherically symmetric solutions give field distributions which have a spherical surface on which the gauge fields become infinite (which is similar to bag models of confinement), and the other solution has a potential which increases at large distances. The cylindrically symmetric solution describes a classical field "string" (flux tube) of the kind which is expected to form between quarks in the dual superconductor picture of confinement. These solutions with classical confining behaviour appear to be typical solutions for the classical SU(3) Yang-Mills equations. This implies that the confining properties of the classical SU(3) Yang-Mills theory are general properties of this theory.

hep-th↗

arXiv1999

Flux Tube Solution in 5D Kaluza-Klein Theory

Spherically symmetric, vacuum solutions in 5D and 7D Kaluza-Klein theory are obtained. These solutions are flux tubes with constant cross-sectional size, located between (+) and (-) Kaluza-Klein's ``electrical'' and ``magnetic'' charges disposed respectively at $\pm\infty$ and filled by constant Kaluza-Klein ``electrical'' and ``magnetic'' fields. These objects are surprisingly similar to the flux tubes which forms between two monopoles in Type-II superconductors and also the hypothesized color field flux tube that is thought to form between two quarks in the QCD vacuum.

gr-qc↗

arXiv1999

Wormholes and Flux Tubes in 5D Kaluza-Klein Theory

In this paper spherically symmetric solutions to 5D Kaluza-Klein theory, with ``electric'' and/or ``magnetic'' fields are investigated. It is shown that the global structure of the spacetime depends on the relation between the ``electrical'' and ``magnetic'' Kaluza-Klein fields. For small ``magnetic'' field we find a wormhole-like solution. As the strength of the ``magnetic'' field is increased relative to the strength of the ``electrical'' field, the wormhole-like solution evolves into a finite or infinite flux tube depending on the strengths of the two fields. For the large ``electric'' field case we conjecture that this solution can be considered as the mouth of a wormhole, with the $G_{55}$, $G_{5t}$ and $G_{5ϕ}$ components of the metric acting as the source of the exotic matter necessary for the formation of the wormhole's mouth. For the large ``magnetic'' field case a 5D flux tube forms, which is similar to the flux tube between two monopoles in Type-II superconductors, or the hypothesized color field flux tube between two quarks in the QCD vacuum.

gr-qc↗

arXiv1998

Quantization of spherically symmetric solution of SU(3) Yang-Mills theory

A recent investigation of the SU(3) Yang-Mills field equations found several classical solutions which exhibited a type of confinement due to gauge fields which increased without bound as $r \to \infty$. This increase of the gauge fields gave these solutions an infinite field energy, raising questions about their physical significance. In this paper we apply some ideas of Heisenberg about the quantization of strongly interacting, non-linear fields to this classical solution and find that at large $r$ this quantization procedure softens the unphysical behaviour of the classical solution, while the interesting short distance behaviour is still maintained. This quantization procedure may provide a general method for approximating the quantum corrections to certain classical field configurations.

hep-th↗

arXiv1998

Quantization of strongly interacting fields

While perturbative techniques work extremely well for weakly interacting field theories (e.g. QED), they are not useful when studying strongly interacting field theories (e.g. QCD at low energies). In this paper we review Heisenberg's idea about quantizing strongly interacting, non-linear fields, and an approximate method of solving the infinite set of Tamm-Dankoff equations is suggested. We then apply this procedure to an infinite energy, classical flux tube-like solution of SU(2) Yang-Mills theory and show that this quantization procedure ameliorates some of the bad behaviour of the classical solution. We also discuss the possible application of this quantization procedure to a recently proposed strongly interacting phonon model of High-$T_c$ superconductors.

hep-th↗