arXiv subjects

David Delphenich

Publications and source records attributed to David Delphenich.

At least 19 recordsLinked to original sources

arXiv2017

Transverse momentum as a source of gravitoelectromagnetism

Momentum can be regarded as a mass current that can be used as the source of the gravitoelectromagnetic field, which is the weak-field gravitational analogue of the classical electromagnetic field. Typically, gravitoelectromagnetic research considers only mass currents of convective type, which are collinear with the velocity vector field, but when one looks at charged fluids that interact with a background electromagnetic field or charged, spinning point-like matter, such as the Frenkel electron, or extended spinning mass distributions, such as the Dirac electron and the Weyssenhoff fluid, one will also encounter transverse momentum. The effects of that transverse momentum on the gravitoelectromagnetic field are investigated.

gr-qc↗

arXiv2015

Pre-metric electromagnetism as a path to unification

It is shown that the pre-metric approach to Maxwell's equations provides an alternative to the traditional Einstein-Maxwell unification program, namely, that electromagnetism and gravitation are unified in a different way that makes the gravitational field a consequence of the electromagnetic constitute properties of spacetime, by way of the dispersion law for the propagation of electromagnetic waves.

gr-qc↗

arXiv2012

The role of integrability in a large class of physical systems

A large class of physical systems involves the vanishing of a 1-form on a manifold as a constraint on the acceptable states. This means that one is always dealing with the Pfaff problem in those cases. In particular, knowing the degree of integrability of the 1-form is often essential, or, what amounts to the same thing, its canonical (i.e., normal) form. This paper consists of two parts: In the first part, the Pfaff problem is presented and discussed in a largely mathematical way, and in the second part, the mathematical generalities thus introduced are applied to various physical models in which the normal form of a 1-form has already been implicitly introduced, such as non-conservative forces, linear non-holonomic constraints, the theory of vortices and equilibrium thermodynamics. The role of integrability in the conservation of energy is a recurring theme.

math-ph↗

arXiv2012

The relativistic Pauli equation

After discussing the way that C2 and the algebra of complex 2x2 matrices can be used for the representation of both non-relativistic rotations and Lorentz transformations, we show that Dirac bispinors can be more advantageously represented as 2x2 complex matrices. One can then give the Dirac equation a form for such matrix-valued wave functions that no longer necessitates the introduction of gamma matrices or a choice for their representation. The minimally-coupled Dirac equation for a charged spinning particle in an external electromagnetic field then implies a second order equation in the matrix-valued wave functions that is of Klein-Gordon type and represents the relativistic analogue of the Pauli equation. We conclude by presenting the Lagrangian form for the relativistic Pauli equation.

physics.gen-ph↗

arXiv2008

Integrability and the variational formulation of non-conservative mechanical systems

It is shown that one can obtain canonically-defined dynamical equations for non-conservative mechanical systems by starting with a first variation functional, instead of an action functional, and finding their zeroes. The kernel of the first variation functional, as an integral functional, is a 1-form on the manifold of kinematical states, which then represents the dynamical state of the system. If the 1-form is exact then the first variation functional is associated with the first variation of an action functional in the usual manner. The dynamical equations then follow from the vanishing of the dual of the Spencer operator that acts on the dynamical state. This operator, in turn, relates to the integrability of the kinematical states. The method is applied to the modeling of damped oscillators.

math-ph↗

arXiv2008

Generalized Madelung transformations for quantum wave equations I: generalized spherical coordinates for field spaces

The Madelung transformation of the space in which a quantum wave function takes its values is generalized from complex numbers to include field spaces that contain orbits of groups that are diffeomorphic to spheres. The general form for the resulting real wave equations then involves structure constants for the matrix algebra that is associated with the group action. The particular cases of the algebras of complex numbers, quaternions, and complex quaternions, which pertain to the Klein-Gordon equation, the relativistic Pauli equation, and the bi-Dirac equation, resp., are then discussed.

hep-th↗

arXiv2007

Transverse geometry and physical observers

It is proposed that the mathematical formalism that is most appropriate for the study of spatially non-integrable cosmological models is the transverse geometry of a one-dimensional foliation (congruence) defined by a physical observer. By that means, one can discuss the geometry of space, as viewed by that observer, without the necessity of introducing a complementary sub-bundle to the line bundle of the observer or a codimension-one foliation transverse to the foliation of the observer. The concept of groups of transverse isometries acting on such a spacetime and the relationship of transverse geometry to spacetime threadings (1+3 decompositions) is also discussed.

gr-qc↗

arXiv2007

Hermitian structures defined by linear electromagnetic constitutive laws

It is demonstrated that when the bundle of 2-forms on a four-dimensional manifold M admits an almost-complex structure any choice of "real + imaginary" subspace decomposition of the bundle defines a conjugation map, as well as a Hermitian structure for the bundle. When the almost-complex structure comes from a linear electromagnetic constitutive law, the real and imaginary parts of the Hermitian structure are then shown to represent the Hamiltonian for an anisotropic three-dimensional electromagnetic oscillator at each point of M and a symplectic structure for each fiber. The complex form of the oscillator equations is also definable in terms of the geometric structures that were introduced.

hep-th↗

arXiv2007

A more direct representation for complex relativity

An alternative to the representation of complex relativity by self-dual complex 2-forms on the spacetime manifold is presented by assuming that that the bundle of real 2-forms is given an almost-complex structure. From this, one can define a complex orthogonal structure on the bundle of 2-forms, which results in a more direct representation of the complex orthogonal group in three complex dimensions. The geometrical foundations of general relativity are then presented in terms of the bundle of oriented complex orthogonal 3-frames on the bundle of 2-forms in a manner that essentially parallels their construction in terms of self-dual complex 2-forms. It is shown that one can still discuss the Debever-Penrose classification of the Riemannian curvature tensor in terms of the representation presented here.

gr-qc↗

arXiv2007

Field/source duality in topological field theories

The relationship between the sources of physical fields and the fields themselves is investigated with regard to the coupling of topological information between them. A class of field theories that we call topological field theories is defined such that both the field and its source represent de Rham cocycles in varying dimensions over complementary subspaces and the coupling of one to the other is by way of an isomorphism of the those cohomology spaces, which we refer to as field/source duality. The deeper basis for such an isomorphism is investigated and the process is described for various elementary physical examples of topological field theories.

hep-th↗

arXiv2005

Symmetries of the equations of pre-metric electromagnetism

The equations of pre-metric electromagnetism are summarized and then formulated as an exterior differential system on the total space of the bundle of 2-forms over the spacetime manifold. The Harrison-Estabrook method of computing the symmetries of the system is then applied, with the result that of the four possible formal algebras of infinitesimal symmetries, the most physically compelling one is the Lie algebra of infinitesimal projective transformations of real four-dimensional projective space.

gr-qc↗

arXiv2005

Spinors and pre-metric electromagnetism

The basic concepts of the formulation of Maxwellian electromagnetism in the absence of a Minkowski scalar product on spacetime are summarized, with particular emphasis on the way that the electromagnetic constitutive law on the space of bivectors over spacetime supplants the role of the Minkowski scalar product on spacetime itself. The complex geometry of the space of bivectors is summarized, with the intent of showing how an isomorphic copy of the Lorentz group appears in that context. The use of complex 3-spinors to represent electromagnetic fields is then discussed, as well as the expansion of scope that the more general complex projective geometry of the space of bivectors suggests.

gr-qc↗

arXiv2005

Projective geometry and special relativity

Some concepts of real and complex projective geometry are applied to the fundamental physical notions that relate to Minkowski space and the Lorentz group. In particular, it is shown that the transition from an infinite speed of propagation for light waves to a finite one entails the replacement of a hyperplane at infinity with a light cone and the replacement of an affine hyperplane - or rest space - with a proper time hyperboloid. The transition from the metric theory of electromagnetism to the pre-metric theory is discussed in the context of complex projective geometry, and ultimately it is proposed that the geometrical issues are more general than electromagnetism, namely, they pertain to the transition from point mechanics to wave mechanics.

gr-qc↗

arXiv2005

Symmetries and pre-metric electromagnetism

The equations of pre-metric electromagnetism are formulated as an exterior differential system on the bundle of exterior differential 2-forms over the spacetime manifold. The general form for the symmetry equations of the system is computed and then specialized to various possible forms for an electromagnetic constitutive law, namely, uniform linear, non-uniform linear, and uniform nonlinear. It is shown that in the uniform linear case, one has four possible ways of prolonging the symmetry Lie algebra, including prolongation to a Lie algebra of infinitesimal projective transformations of a real four-dimensional projective space. In the most general non-uniform linear case, th effect of non-uniformity on symmetry seems inconclusive in the absence of further specifics, and in the uniform nonlinear case, the overall difference from the uniform linear case amounts to a deformation of the electromagnetic constitutive tensor by the electromagnetic fields strengths, which induces a corresponding deformation of the symmetry Lie algebra that was obtained in the uniform linear case.

gr-qc↗

arXiv2004

Spacetime G-structures II: geometry of the ground states

This article is a continuation of a previous work that dealt with the topological obstructions to the reductions of the bundle of linear frames on a spacetime manifold for a particular chain of subgroups of GL(4). In this article, the corresponding geometrical information, such as connections, torsion, curvature, and automorphisms of the reductions will be discussed. The details are elaborated upon for a certain sequence of reductions of GL(M) when M is a four-dimensional spacetime manifold.

gr-qc↗

arXiv2004

Possibilities for a Causal Interpretation for Quantum Mechanics

The basic physical problems that necessitated the emergence of quantum physics are summarized, along with the elements of wave mechanics and its traditional statistical interpretation. Alternative interpretations to the statistical one, such as the hydrodynamical and optical interpretations, nonlinear waves and nonlinear electrodynamics, and the conception of spacetime as an ordered medium are reviewed.

quant-ph↗

arXiv2004

Some Mathematical Issues Pertaining to Translational Gauge Theories

Some mathematical aspects of using the translation group as an internal symmetry group in a gauge field theory are presented and discussed. The traditional manner in which gravitation can be accounted for by the introduction of a global frame field on a parallelizable spacetime is reviewed. It is then discussed in the more general context of a global frame field on the bundle of linear frames. In the process, the elements of variational field theory for physical fields defined on G-structures are set down. It is suggested that it is probably more proper to attribute gravitation to a reduction of the bundle of linear frames to {e} -- at least over a generic submanifold of spacetime -- than to a reduction to the Lorentz group since the Lorentz group is more intrinsic to electromagnetism and gravitation has the character of a "residual" symmetry of spacetime at the astrophysical level.

gr-qc↗

arXiv2003

Nonlinear Electrodynamics and QED

The limits of linear electrodynamics are reviewed, and possible directions of nonlinear extension are explored. The central theme is that the qualitative character of the empirical successes of quantum electrodynamics must be used as a guide for understanding the nature of the nonlinearity of electrodynamics at the subatomic level. Some established theories of nonlinear electrodynamics, namely, those of Mie, Born, and Infeld are presented in the language of the modern geometrical and topological methods of mathematical physics. The manner by which spacetime curvature and topology can affect electromagnetism is also reviewed. Finally, the phenomena of nonlinear optics are discussed as a possible guide to building one's intuition regarding the process of extending electrodynamics into nonlinearity in a manner that is consistent with the qualitative and empirical results of quantum electrodynamics.

hep-th↗