Gravito-electromagnetism versus electromagnetism

The paper contains a discussion of the properties of the gravito-magnetic interaction in non stationary conditions. A direct deduction of the equivalent of Faraday-Henry law is given. A comparison is made between the gravito-magnetic and the electro-magnetic induction, and it is shown that there is no Meissner-like effect for superfluids in the field of massive spinning bodies. The impossibility of stationary motions in directions not along the lines of the gravito-magnetic field is found. Finally the results are discussed in relation with the behavior of superconductors.Comment: 13 Pages, LaTeX, 1 EPS figure, to appear in European Journal of Physic

Electromagnetism in terms of quantum measurements

We consider the question whether electromagnetism can be derived from quantum physics of measurements. It turns out that this is possible, both for quantum and classical electromagnetism, if we use more recent innovations such as smearing of observables and simultaneous measurability. In this way we justify the use of von Neumann-type measurement models for physical processes. We apply operational quantum measurement theory to gain insight in fundamental aspects of quantum physics. Interactions of von Neumann type make the Heisenberg evolution of observables describable using explicit operator deformations. In this way one can obtain quantized electromagnetism as a measurement of a system by another. The relevant deformations (Rieffel deformations) have a mathematically well-defined "classical" limit which is indeed classical electromagnetism for our choice of interaction

Emergent Gravity from Noncommutative Spacetime

We showed before that self-dual electromagnetism in noncommutative (NC) spacetime is equivalent to self-dual Einstein gravity. This result implies a striking picture about gravity: Gravity can emerge from electromagnetism in NC spacetime. Gravity is then a collective phenomenon emerging from gauge fields living in fuzzy spacetime. We elucidate in some detail why electromagnetism in NC spacetime should be a theory of gravity. In particular, we show that NC electromagnetism is realized through the Darboux theorem as a diffeomorphism symmetry G which is spontaneously broken to symplectomorphism H due to a background symplectic two-form $B_{\mu\nu}=(1/\theta)_{\mu\nu}$, giving rise to NC spacetime. This leads to a natural speculation that the emergent gravity from NC electromagnetism corresponds to a nonlinear realization G/H of the diffeomorphism group, more generally its NC deformation. We also find some evidences that the emergent gravity contains the structure of generalized complex geometry and NC gravity. To illuminate the emergent gravity, we illustrate how self-dual NC electromagnetism nicely fits with the twistor space describing curved self-dual spacetime. We also discuss derivative corrections of Seiberg-Witten map which give rise to higher order gravity.Comment: 50 pages; Cosmetic revision and updated reference

Maxwell-Lorentz Dynamics of Rigid Charges

We establish global existence and uniqueness of the dynamics of classical electromagnetism with extended, rigid charges and fields which need not to be square integrable. We consider also a modified theory of electromagnetism where no self-fields occur. That theory and our results are crucial for approaching the as yet unsolved problem of the general existence of dynamics of Wheeler Feynman electromagnetism, which we shall address in the follow up paper.Comment: 32 pages, revised Introduction, typos correcte

Nonseparability, Classical and Quantum

This paper examines the implications of the holonomy interpretation of classical electromagnetism. As has been argued by Richard Healey and Gordon Belot, classical electromagnetism on this interpretation evinces a form of nonseparability, something that otherwise might have been thought of as confined to non-classical physics. Consideration of the differences between this classical nonseparability and quantum nonseparability shows that the nonseparability exhibited by classical electromagnetism on the holonomy interpretation is closer to separability than might at first appear

Gravito-electromagnetism

We develop and apply a fully covariant 1+3 electromagnetic analogy for gravity. The free gravitational field is covariantly characterized by the Weyl gravito-electric and gravito-magnetic spatial tensor fields, whose dynamical equations are the Bianchi identities. Using a covariant generalization of spatial vector algebra and calculus to spatial tensor fields, we exhibit the covariant analogy between the tensor Bianchi equations and the vector Maxwell equations. We identify gravitational source terms, couplings and potentials with and without electromagnetic analogues. The nonlinear vacuum Bianchi equations are shown to be invariant under covariant spatial duality rotation of the gravito-electric and gravito-magnetic tensor fields. We construct the super-energy density and super-Poynting vector of the gravitational field as natural U(1) group invariants, and derive their super-energy conservation equation. A covariant approach to gravito-electric/magnetic monopoles is also presented.Comment: 14 pages. Version to appear in Class. Quant. Gra

Knotted solutions, from electromagnetism to fluid dynamics

Knotted solutions to electromagnetism and fluid dynamics are investigated, based on relations we find between the two subjects. We can write fluid dynamics in electromagnetism language, but only on an initial surface, or for linear perturbations, and we use this map to find knotted fluid solutions, as well as new electromagnetic solutions. We find that knotted solutions of Maxwell electromagnetism are also solutions of more general nonlinear theories, like Born-Infeld, and including ones which contain quantum corrections from couplings with other modes, like Euler-Heisenberg and string theory DBI. Null configurations in electromagnetism can be described as a null pressureless fluid, and from this map we can find null fluid knotted solutions. A type of nonrelativistic reduction of the relativistic fluid equations is described, which allows us to find also solutions of the (nonrelativistic) Euler's equations.Comment: 36 pages, 3 figure