In theoretical physics, paradoxes are good. That’s paradoxical, since a paradox appears to be a contradiction, and contradictions imply serious error. But Nature cannot realize contradictions. When our physical theories lead to paradox we must find a way out. Paradoxes focus our attention, and we think harder. When David Gross and I began the work that led to this Nobel Prize [1, 2, 3, 4], in 1...

We present a broad review on black holes. We analyse some of the fundamental concepts in black hole theory, the observational and theoretical status of stellar and galactic black holes, and their appearance

Particles with millicharge q and sub-eV mass can be produced in photon-photon collisions, distorting the energy spectrum of the Cosmic Microwave Background. We derive the conservative bound q < ∼ 10 −7 e (as well as model-dependent bounds two orders of magnitude stronger), incompatible with proposed interpretations of the PVLAS anomaly based on millicharged production or on millicharged-mediate...

In this paper we examine the effect of introducing an Electromagnetic metamaterial into a Travelling Wave structure to mediate inverse Cherenkov acceleration. Electromagnetic metamaterials are artificial materials that consist of macroscopic structures that yield an effective permittivity and permeability less than zero. The properties of metamaterials are highly frequency dependent and give ri...

During the first years of the twentieth century, the core subject in preclinical medical education was anatomy. Will that still be the case in the first part of the next century? The answer could lie in the experiments at the Large Hadron Collider where the nature of matter is being studied. Wave-particle duality, atomic and molecular interactions will perhaps illuminate previously unexplained ...

In a set of two papers, we propose to study an old-standing problem, namely the electromagnetic interaction for particles of arbitrary spin. Based on the assumption that light-cone helicity at tree level and Q = 0 should be conserved non-trivially by the electromagnetic interaction, we are able to derive all the natural electromagnetic moments for a pointlike particle of any spin. In this first...

The linear momentum of an elementary charged particle is normally written as mv. This paper shows that it can equally be written as qA. This A is the self−induced vector potential, acting on each tiny element of the charge, by virtue of all the rest of the charge (in motion). |qA| = (q2μ0v/4π)<1/|r|>, where |r| is comparable with the “classical radius” of the elementary particle, i.e. the radiu...

We review the formulation of the problem of the electromagnetic self-interaction of a relativistic charged particle in the framework of the manifestly covariant classical mechanics of Stueckelberg, Horwitz, and Piron. The gauge fields of this theory, in general, cause the mass of the particle to change. We show that the nonlinear Lorentz force equation for the self-interaction resulting from th...

There are known problems of Lorentz-Dirac equation for moving with acceleration charged particle in classical electrodynamics. The model of extended in one dimension particle is proposed and shown that electromagnetic self-interaction can lead (with appropriate choice of retarded and advanced interactions) to zero change in particle momentum. The hypothesis is formulated: all relativistic inter...