Helicity, spin, and infra-zilch of light: A Lorentz covariant formulation

Journal Article · Sun Aug 15 04:00:00 EDT 2021 · Annals of Physics

DOI:https://doi.org/10.1016/J.AOP.2021.168535· OSTI ID:23183228

Aghapour, Sajad ^[1]; Andersson, Lars ^[2]; Rosquist, Kjell ^[3]

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1. School of Physics, Institute for Research in Fundamental Sciences (IPM), Tehran (Iran, Islamic Republic of)
2. Albert Einstein Institute, Am Mühlenberg 1, D-14476 Potsdam (Germany)
3. AlbaNova University Center, Stockholm University, Department of Physics, SE 106 91, Stockholm (Sweden)

Highlights: • Spin and orbital parts of angular momentum. • The helicity tensor contains the helicity, spin and infra-zilch currents. • The helicity tensor is a Noether current for a duality-symmetric action. • Symmetry generator for the helicity tensor. • The helicity tensor is conserved in Lorenz gauge. In this paper, a novel conserved Lorentz covariant tensor, termed the helicity tensor, is introduced in Maxwell theory. The conservation of the helicity tensor expresses the conservation laws contained in the helicity array, introduced by Cameron et al. (2012), including helicity, spin, as well as the spin-flux or infra-zilch. The Lorentz covariance of the helicity tensor is in contrast to previous formulations of the helicity hierarchy of conservation laws, which required the non-Lorentz covariant transverse gauge. The helicity tensor is shown to arise as a Noether current for a variational symmetry of a duality-symmetric Lagrangian for Maxwell theory. This symmetry transformation generalizes the duality symmetry and includes the symmetry underlying the conservation of the spin part of the angular momentum.

• OSTI ID: 23183228
• Journal Information: Annals of Physics, Journal Name: Annals of Physics Vol. 431; ISSN 0003-4916; ISSN APNYA6
• Country of Publication: United States
• Language: English

Related Subjects

71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
DUALITY
LAGRANGIAN FUNCTION
SPIN
SYMMETRY
TENSORS
VARIATIONAL METHODS