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Related papers: Weyl spinors and the helicity formalism

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The Klein-Gordon equation describes the wave-like behavior of spinless particles since it is Lorentz invariant. While it seemed initially ripe for explaining the electronic structure of the hydrogen atom, the lack of a unconditional…

Quantum Physics · Physics 2025-02-07 P. -A. Gourdain

The formalism for the spin interactions in the front form (light-cone) is re-phrased in terms of an instant form formalism. It is shown how to unitarily transform the Brodsky-Lepage spinors to Bj{\o}rken-Drell spinors and to re-phrase the…

High Energy Physics - Phenomenology · Physics 2007-05-23 Hans-Christian Pauli

The nature of spin current and the separation of charge current and spin current are two of the fundamental questions in spintronics. For this purpose the classical limit of the Maxwell-Dirac theory is investigated in the present…

General Physics · Physics 2017-07-14 S C Tiwari

The "spin-up" and "spin-down" projections of the second order, chiral form of Dirac Theory are shown to fit a superposition of forms predicted in an earlier classical, complex scalar gauge theory (April, 1992 Class. Quantum Grav.). In some…

General Relativity and Quantum Cosmology · Physics 2017-06-30 J. E. Rankin

An introduction to spin techniques in particle physics is given. Among the topics covered are: helicity formalism and its applications to the decay and scattering of spin-1/2 and spin-1 particles, techniques for evaluating helicity…

High Energy Physics - Phenomenology · Physics 2009-09-25 Howard E. Haber

The Weyl double copy formalism, which relates the Weyl spinor with the square of the field strength, is studied in the context of Hassan-Rosen bigravity for stationary and time-dependent solutions. We consider the dyonic Kerr-Newman-(A)dS…

General Relativity and Quantum Cosmology · Physics 2025-10-03 Hugo García-Compeán , César I. Ramos

In this paper we derive a fully relativistic kinetic theory for spin-1/2 particles and its coupling to Maxwell's equations, valid in the long scale-length limit, where the fields vary on a scale much longer than the localization of the…

Plasma Physics · Physics 2017-08-30 Robin Ekman , Felipe A. Asenjo , Jens Zamanian

We consider the most general action for gravity which is quadratic in curvature. In this case first order and second order formalisms are not equivalent. This framework is a good candidate for a unitary and renormalizable theory of the…

High Energy Physics - Theory · Physics 2017-12-22 Enrique Alvarez , Jesus Anero , Sergio Gonzalez-Martin

Inspired by the flow description of su(N) colour calculations, we recently showed how to simplify the spinor-helicity formalism (at the algebra level two copies of complexified su(2)) by treating each Weyl spinor as part of a flow line with…

High Energy Physics - Phenomenology · Physics 2021-10-11 Joakim Alnefjord , Andrew Lifson , Christian Reuschle , Malin Sjodahl

A rigorous \textit{ab initio} derivation of the (square of) Dirac's equation for a single particle with spin is presented. The general Hamilton-Jacobi equation for the particle expressed in terms of a background Weyl's conformal geometry is…

Quantum Physics · Physics 2011-07-19 Enrico Santamato , Francesco De Martini

For Dirac particles interacting with external fields, we use the exact operator of the Foldy-Wouthuysen transformation obtained by Eriksen and rigorously derive a leading correction in the weak-field approximation to the known relativistic…

Quantum Physics · Physics 2025-05-12 Alexander J. Silenko

Using the example of a Dirac particle in external static fields, Dirac theory is reformulated as a one-particle quantum theory in the space of normalized two-component spinors. In this formulation, the Dirac operator ``splits'' into two…

General Physics · Physics 2026-05-29 N. L. Chuprikov

In a recent paper [1], it has been proposed that relativistic wave-particle duality can be embodied in a relation that shows that the four-velocity of a particle is proportional to the Dirac four-current. In this note we bring out some…

General Relativity and Quantum Cosmology · Physics 2022-02-13 Carl F. Diether , III , Joy Christian

We present a second-quantized field theory of massive spin one-half particles or antiparticles in the presence of a weak gravitational field treated as a spin two external field in a flat Minkowski background. We solve the difficulties…

General Relativity and Quantum Cosmology · Physics 2016-12-07 Christian J. Bordé , Jean-Claude Houard , Alain Karasiewicz

We examine recent advancements of the spinor helicity formalism of massive particles. Technical aspects about the formulation of massive helicity spinors are presented in detail to analyze the projective-geometry kinematics of helicity…

High Energy Physics - Theory · Physics 2026-03-03 Camille Gomez-Laberge

The relativistic approach to electroweak properties of two-particle composite systems developed in Ref. [A.F.Krutov, V.E.Troitsky, Phys.Rev.C. 65 (2002) 045501] is generalized here to the case of nonzero spin. In developed technique the…

High Energy Physics - Phenomenology · Physics 2009-02-06 A. F. Krutov , V. E. Troitsky

Determining the spin of any new particle and measuring its couplings to other particles and/or itself are crucial in reconstructing the structure of any quantum field theory containing the particle. A general helicity formalism is employed…

High Energy Physics - Phenomenology · Physics 2019-03-05 Seong Youl Choi , Jae Hoon Jeong , Ji Ho Song

Within this article one finds the statement of the Klein-Gordon problem within the real Hilbert space formalism ($\mathbbm R$HS) in terms of complex wave functions, and in terms of quaternionic wave functions as well. The complex…

Quantum Physics · Physics 2025-10-28 Cristiano Rosa , Sergio Giardino

The De Donder-Weyl (DW) covariant Hamiltonian formulation of Palatini first-order Lagrangian of vielbein (tetrad) gravity and its precanonical quantization are presented. No splitting into the space and time is required in this formulation.…

General Relativity and Quantum Cosmology · Physics 2015-01-28 I. V. Kanatchikov

We discuss the tight-binding models of solid state physics with the $Z_2$ sublattice symmetry in the presence of elastic deformations, and their important particular case -the tight binding model of graphene. In order to describe the…

Mesoscale and Nanoscale Physics · Physics 2019-08-13 I. V. Fialkovsky , M. A. Zubkov