4,959 research outputs found

    The (1,0)+(0,1) spinor description of the photon field and its preliminary applications

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    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

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    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

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    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 4π4\pi) 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

    Photons inside a waveguide as massive particles

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    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

    Zitterbewegung at the level of quantum field theory

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    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

    Gradient and Stability Estimates of Heat Kernels for Fractional Powers of Elliptic Operator

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    Gradient and stability type estimates of heat kernel associated with fractional power of a uniformly elliptic operator are obtained. LpL^p-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

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    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

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    In this paper, we obtain the upper bounds to the third Hankel determinants for starlike functions of order α\alpha, convex functions of order α\alpha and bounded turning functions of order α\alpha. 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

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    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

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    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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