Reality of Time

The meaning of instantaneous action at a distance is elucidated. It is shown that the absence of a medium to transmit action (usually referred to as AAD in the literature) and instantaneous action are not identical. Since the term "instantaneous" is incompatible with relativity and field theory, a critique is presented on the concept of time in relativity. It is argued that relativity does not deal with the nature of time. Physical reality of the absolute time is envisaged, and instantaneous action is proposed to be a natural consequence of it. Possibly gravity is such kind of a force, however the electromagnetic force, though envisaged as direct particle interaction (i.e. without intermediary fields) can not be instantaneous.Comment: Invited essay published in "Action at a Distance in Modern Physics:Pro & Contra", edited by A.E. Chubykalo et al(Nova NY 1999), pp. 184-192, e-mail:[email protected]

On the anomalous extreme ultraviolet emission lines in helium-hydrogen plasma

The idea of photonic de Broglie waves is discussed in the context of recent obsrved lines in the helium-hydrogen plasma

The nature of electronic charge

Advances in gauge theories and unified theories have not thrown light on the meaning of electron. The problem of the origin of electronic charge is made precise, new insights gained from Weyl space are summarized, and the origin of charge in terms of fractional spin is suggested. New perspective on the abelian Chern-Simons theory is presented to explain charge.Comment: Final version as publishe

Photon Spin, Zero-point Energy and Black-body radiation

A critical review of the obscure nature of the contribution of spin energy to the energy of the electromagnetic field is presented. It is proposed that the total energy of photon h\nu comprises of kinetic and spin parts each equal to h\nu/2. Classical magnetic field is reinterpreted as angular momentum flux of photon fluid. The black-body radiation law is revisited in the light of new significance of the zero-point energy proposed here.Comment: Submitted for publicatio

Unimodular relativity and cosmological constant : Comments

We show that the conclusion that matter stress-energy tensor satisfies the usual covariant continuity law, and the cosmological constant is still a constant of integration arrived at by Finkelstein et al (42, 340, 2001) is not valid.Comment: Submitted to Journal of Mathematical Physics; correspondence to [email protected]

Time varying velocity of light

Recently there has been a lot of intersest in the superluminal phenomena, and time varying velocity of light cosmological models. More than two decades ago at Einstein centenary symposium, Nagpur I had put forward space-time interaction hypothesis. One of its predictions was that velocity of light decreased with the age of Universe. In view of the profoundness of the hypothesis the original paper is reproduced here. We also mention that in a paper "Quasars, Tachyons and the early universe" proc. Einstein found. Intnl. 2(3), 1985 pp 69-75, it was suggested that, "The boundary region of the universe being the source of radiation, the slowing down of the speed of radiation from $4.4 \times 10^{10}$ cm/sec at $t_A = 10^{10}$ yrs. to the present value of $3 \times 10^{10}$ cm/sec should show up as a large red shifts. The successive boundary region radiations at various epoch will give rise to a wide range of red shifts. Therefore, defining quasars as the objects having two properties: large red shifts and powerful emission of radiations, we would like to identify these objects as the boundary regions of the universe".Comment: Published in Proceedings of "Einstein Centenary Symposium, 1980 at Nagpur, Indi

Viscous Spacetime Fluid and Higher Curvature Gravity

The Einstein field equation as an equation of state of a thermodynamical system of spacetime is reconsidered in the present Letter. We argue that a consistent interpretation leads us to identify scalar curvature and cosmological constant terms representing the bulk viscosity of the spacetime fluid. Since Einstein equation itself corresponds to a near-equilibrium state in this interpretation invoking $f(R)$ gravity for nonequilibrium thermodynamics is not required. A logically consistent generalization to include the effect of so called 'tidal forces' due to the Riemann curvature is presented. A new equation of state for higher curvature gravity is derived and its physical interpretation is discussed.Comment: 4 pages, no figures, submitted for publicatio

Nature of the Angular Momentum of Light: Rotational Energy and Geometric Phase

The nature of intrinsic/extrinsic character of angular momentum is defined in terms of the kind of the associated rotational energy of the light. The salient features of the spin energy of light and photon are highlighted. Spin angular momentum is intrinsic while orbital angular momentum possesses quasi-intrinsicness only if the vortex-like singularities are present. The claimed spin to orbital angular momentum conversion is interpreted in terms of spin redirection geometric phase. It is pointed out that this interpretation validates our angular momentum holonomy conjecture.Comment: Submitted for publicatio

Magnon-phonon conversion experiment and phonon spin

Recent experiment demonstrates magnon to phonon conversion in a YIG film under the application of a non-uniform magnetic field. Light scattered from phonons is observed to change its polarization state interpreted by the authors signifying phonon spin. In this note we argue that the experimental data merely shows the exchange of angular momentum $\pm \hbar$ per photon. We suggest that it has physical origin in the orbital angular momentum of phonons. The distinction between spin and orbital parts of the total angular momentum, and between phonons and photons with added emphasis on their polarizations is explained. The main conclusion of the present note is that phonon spin hypothesis is unphysical.Comment: 4 pages, a new section added to elaborate the discussion on phonon-photon analog

Comment on "Cyclotron resonance study of the electron and hole velocity in graphene monolayers"

In this comment it is pointed out that the electron velocity of the same order as observed in graphene had been measured in GaAs submicron devices long ago. Particle- antiparticle asymmetry related with electron and hole effective masses in graphene seems puzzling as hole in a condensed matter system cannot be treated as anti-electron. It is argued that there should be a universal electrodynamics for QHE and superconductivity. In this context attention is drawn to the new approach based on massless electron and the interpretation that magnetic field represents angular momentum of the photon fluid. Measurement of electron velocity in graphene and GaAs in parallel is suggested for testing the massless electrodynamics.Comment: 2 pages no figure