5,271 research outputs found
The (1,0)+(0,1) spinor description of the photon field and its preliminary applications
Because spatio-temporal tensors are associated with the Lorentz group,
whereas spinors are associated with its covering group SL(2, C), one can
associate with every tensor a spinor (but not vice versa). In particular, the
(1,0)+(0,1) representation of SL(2, C) can provide a six-component spinor
equivalent to the electromagnetic field tensor. The chief aim of this work is
to develop the (1,0)+(0,1) description for the electromagnetic field in the
absence of sources, rigorously and systematically, which should be useful if we
are to deal with those issues involving with single-photon states and the
angular momentum of light, etc. Based on our formalism, the quantum theory and
some symmetries of the photon field can be discussed in a new manner, and the
spin-orbit interaction of photons can be described in a form that is closely
analogous to that of the Dirac electron. Moreover, in terms of the (1,0)+(0,1)
description, one can treat the photon field in curved spacetime via spin
connection and the tetrad formalism, which is of great advantage to study the
gravitational spin-orbit coupling of photons.Comment: 60 pages, no figure. It will provide a comprehensive reference for
some of our future work
Reconsideration of photonic tunneling through undersized waveguides
All the previous studies on photonic tunneling are just based on a simple and
directly analogy with a one-dimensional quantum-mechanical tunneling, without
taking into account the horizontal structure of electromagnetic waves along the
waveguide, such that they are oversimplified and incomplete. Here we present a
more serious deliberation on photonic tunneling through cut-off waveguides, and
obtain a strictly theoretical model with some new results.Comment: 22 pages, no figur
New interpretation to zitterbewegung
In previous investigations on zitterbewegung(zbw) of electron, it is believed
that the zbw results from some internal motion of electron. However, all the
analyses are made at relativistic quantum mechanical level. In framework of
quantum field theory (QFT), we find that the origin of zbw is different from
previous conclusion. Especially, some new interesting conclusions are derived
at this level: 1) the zbw arises from the rapid to-and-fro polarization of the
vacuum in the range of the Compton wavelength (divided by ) of the
electron, which offer the four-dimensional(4D) spin and intrinsic
electromagnetic-moment tensor to the electron; 2) Any attempt that attributes
spin (rather than double the spin) of the electron to some kind of orbital
angular momentum would not be successful; 3) the macroscopic classical speed of
the Dirac vacuum medium vanish in all inertial systems.Comment: 5 pages, no figures, revte
Zitterbewegung at the level of quantum field theory
Traditionally, the zitterbewegung (ZB) of the Dirac electron has just been
studied at the level of quantum mechanics. Seeing that the fact that an old
interest in ZB has recently been rekindled by the investigations on spintronic,
graphene, and superconducting systems, etc., in this paper we present a
quantum-field-theory investigation on ZB and obtain the conclusion that, the ZB
of an electron arises from the influence of virtual electron-positron pairs (or
vacuum fluctuations) on the electron.Comment: 10 pages, no figure, to be published in Chinese Physic
Photons inside a waveguide as massive particles
In the paper, we show that there exists a close analogy between the behavior
of de Broglie matter waves and that of electromagnetic waves inside a hollow
waveguide, such that the guided photons can be treated as free massive
particles subject to a relativistic quantum-mechanical equation. Inspired by
the effective rest mass of guided photons and the zitterbewegung phenomenon of
the Dirac electron, at variance with the well-known Higgs mechanism we present
some different heuristic ideas on the origin of mass.Comment: 14 pages, no figur
Gradient and Stability Estimates of Heat Kernels for Fractional Powers of Elliptic Operator
Gradient and stability type estimates of heat kernel associated with
fractional power of a uniformly elliptic operator are obtained. -operator
norm of semigroups associated with fractional power of two uniformly elliptic
operators are also obtained.Comment: 7 page
On a problem of Bharanedhar and Ponnusamy involving planar harmonic mappings
In this paper, we give a negative answer to a problem presented by
Bharanedhar and Ponnusamy (Rocky Mountain J. Math. 44: 753--777, 2014)
concerning univalency of a class of harmonic mappings. More precisely, we show
that for all values of the involved parameter, this class contains a
non-univalent function. Moreover, several results on a new subclass of
close-to-convex harmonic mappings, which is motivated by work of Ponnusamy and
Sairam Kaliraj (Mediterr. J. Math. 12: 647--665, 2015), are obtained.Comment: 11 pages, 2 figures. To appear in Rocky Mountain J. Mat
On third Hankel determinants for subclasses of analytic functions and close-to-convex harmonic mappings
In this paper, we obtain the upper bounds to the third Hankel determinants
for starlike functions of order , convex functions of order
and bounded turning functions of order . Furthermore, several relevant
results on a new subclass of close-to-convex harmonic mappings are obtained.
Connections of the results presented here to those that can be found in the
literature are also discussed.Comment: 13 page
Spin-orbit couplings of quantum fields in Schwarzschild spacetime
In Schwarzschild spacetime, the gravitational spin-orbit couplings of the
massless Dirac field and the photon field can be studied in a unified way. In
contrary to the previous investigations presented mainly at the
quantum-mechanical level, our work is presented at the level of quantum field
theory without resorting to the Foldy-Wouthuysen transformation. If massless
Dirac particles and photons have the same momentums, their energy-level
splittings due to the gravitational spin-orbit couplings are the same. Massless
Dirac particles and photons coming from the Hawking radiations are partially
polarized as long as their original momentums are not parallel to the radial
direction of a Schwarzschild black hole.Comment: 13 pages, no figur
Some new insights on the statistical origin of the Bekenstein-Hawking entropy I: Some heuristic arguments
Now that the Bekenstein-Hawking entropy has been found within the traditional
theory, its physical interpretation should hide in quantum field theory in
curved spacetime (only its quantum corrections require a detailed knowledge of
quantum gravity). However, to interpret the statistical origin of the
Bekenstein-Hawking entropy, there have developed many microscopic pictures,
some of them are based on the theories that themselves remain to be
experimentally verified, while some cite the Hawking temperature formula and
actually argue in circle (and then they have not provided more information than
the seminal work of Bekenstein and Hawking). Within quantum field theory in
curved spacetime (without introducing any new hypothesis), it is inevitable for
us to attribute the Bekenstein-Hawking entropy to entanglement entropy. In the
first part we just provide a heuristic argument, a rigorous theoretical model
will be presented in our next work.Comment: 21 pages, no figure. The first par
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