8,090 research outputs found

### 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

### 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

### 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

### 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]

### Electric Charge, Fractional Spin and Flux

Ratio of electron charge radius and Compton wavelength of electron is known
to be equal to the dimensionless electromagnetic coupling constant $e^2 /\hbar
c$. It is pointed out that the coupling constant has two alternative
interpretations: as a ratio of two angular momenta since Planck constant has
the dimension of angular momentum, and two flux quanta $e$ and $hc/e$. We argue
that it has deep physical significance such that the electronic charge becomes
flus itself and at a fundamental level fractional spin of quantized vortex. A
unified perspective of the three interpretations of the coupling constant is
presented invoking the new interpretation of the magnetic moment of the
electron comprising of three terms. A critical discussion on the past attempts
to give fundamental importance to magnetism and flux quantum is given and the
implication on the unification quest of our ideas is outlined.Comment: To be submitted for publicatio

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