scholarly journals Searches for the Role of Spin and Polarization in Gravity: A Five-Year Update

2016 ◽  
Vol 40 ◽  
pp. 1660010 ◽  
Author(s):  
Wei-Tou Ni
Keyword(s):  
Electromagnetic Wave ◽  
Electron Spin ◽  
Equivalence Principle ◽  
Poincaré Group ◽  
Universal Gravitation ◽  
Poincare Group ◽  
Fundamental Particles ◽  
Spacetime Structure ◽  
Constitutive Tensor

Searches for the role of spin in gravitation dated before the firm establishment of the electron spin in 1925. Since mass and spin, or helicity in the case of zero mass, are the Casimir invariants of the Poincaré group and mass participates in universal gravitation, these searches are natural steps to pursue. In this update, we report on the progress on this topic in the last five years after our last review. We begin with how is Lorentz/Poincaré group in local physics arisen from spacetime structure as seen by photon and matter through experiments/observations. The cosmic verification of the Galileo Equivalence Principle for photons/electromagnetic wave packets (Universality of Propagation in spacetime independent of photon energy and polarization, i.e. nonbirefringence) constrains the spacetime constitutive tensor to high precision to a core metric form with an axion degree and a dilaton degree of freedom. Hughes-Drever-type experiments then constrain this core metric to agree with the matter metric. Thus comes the metric with axion and dilation. In local physics this metric gives the Lorentz/Poincaré covariance. Constraints on axion and dilaton from polarized/unpolarized laboratory/astrophysical/cosmic experiments/observations are presented. In the end, we review the theoretical progress on the issue of gyrogravitational ratio for fundamental particles and the experimental progress on the measurements of possible long range/intermediate range spin-spin, spin-monopole and spin-cosmos interactions.

scholarly journals Equivalence principles, spacetime structure and the cosmic connection

2016 ◽  
Vol 25 (04) ◽  
pp. 1630002 ◽  
Author(s):  
Wei-Tou Ni
Keyword(s):  
Electromagnetic Wave ◽  
Equivalence Principle ◽  
Light Cone ◽  
Empirical Support ◽  
Linear Regime ◽  
Polarization Rotation ◽  
Fundamental Particles ◽  
Spacetime Structure ◽  
Linear Scheme ◽  
Constitutive Tensor

After reviewing the meaning of various equivalence principles and the structure of electrodynamics, we give a fairly detailed account of the construction of the light cone and a core metric from the equivalence principle for photons (no birefringence, no polarization rotation and no amplification/attenuation in propagation) in the framework of linear electrodynamics using cosmic connections/observations as empirical support. The cosmic nonbirefringent propagation of photons independent of energy and polarization verifies the Galileo Equivalence Principle (Universality of Propagation) for photons/electromagnetic wave packets in spacetime. This nonbirefringence constrains the spacetime constitutive tensor to high precision to a core metric form with an axion degree and a dilaton degree of freedom. Thus comes the metric with axion and dilation. Constraints on axion and dilaton from astrophysical/cosmic propagation are reviewed. Eötvös-type experiments, Hughes–Drever-type experiments, redshift experiments then constrain and tie this core metric to agree with the matter metric, and hence a unique physical metric and universality of metrology. We summarize these experiments and review how the Galileo equivalence principle constrains the Einstein Equivalence Principle (EEP) theoretically. In local physics this physical metric gives the Lorentz/Poincaré covariance. Understanding that the metric and EEP come from the vacuum as a medium of electrodynamics in the linear regime, efforts to actively look for potential effects beyond this linear scheme are warranted. We emphasize the importance of doing Eötvös-type experiments or other type experiments using polarized bodies/polarized particles. We review the theoretical progress on the issue of gyrogravitational ratio for fundamental particles and update the experimental progress on the measurements of possible long range/intermediate range spin–spin, spin–monopole and spin–cosmos interactions.

scholarly journals THE TWO WAYS OF GAUGING THE POINCARÉ GROUP

2009 ◽  
Vol 06 (07) ◽  
pp. 1115-1134
Author(s):  
A. SPIRO ◽  
S. TANTUCCI
Keyword(s):  
Gauge Theory ◽  
Equivalence Principle ◽  
Gauge Fields ◽  
Poincaré Group ◽  
Poincare Group ◽  
Gauge Transformations ◽  
Theory Of Gravity ◽  
Explicit Expressions

A description of how a theory of gravity can be considered as a gauge theory (in the sense of Trautman) of the Poincaré group is given. As a result, it is shown that a gauge theory of this kind is consistent with the Equivalence Principle only if the Lagrangian and the constraints are preserved not only by the gauge transformations but also by an additional family of transformations, called pseudo-translations. Explicit expressions of pseudo-translations and of their action on gravitational gauge fields are given. They are expected to be useful for geometric interpretations of their analogues in supergravity theories.

scholarly journals Massless finite and infinite spin representations of Poincaré group in six dimensions

2021 ◽  
pp. 136064
Author(s):  
I.L. Buchbinder ◽  
S.A. Fedoruk ◽  
A.P. Isaev ◽  
M.A. Podoinitsyn
Keyword(s):  
Poincaré Group ◽  
Poincare Group ◽  
Six Dimensions ◽  
Spin Representations

scholarly journals Completing Multiparticle Representations of the Poincaré Group

2021 ◽  
Vol 127 (4) ◽  
Author(s):  
Csaba Csáki ◽  
Sungwoo Hong ◽  
Yuri Shirman ◽  
Ofri Telem ◽  
John Terning
Keyword(s):  
Poincaré Group ◽  
Poincare Group

TWISTED POINCARE GROUP AND SPIN-STATISTICS

2005 ◽  
Vol 20 (27) ◽  
pp. 6268-6277 ◽  
Author(s):  
ALEKSANDR PINZUL
Keyword(s):  
Field Theory ◽  
Tensor Product ◽  
Poincaré Group ◽  
Commutative Field ◽  
Poincare Group ◽  
Quantized Fields

Recently it has been shown that it is possible to retain the Lorentz-invariant interpretation of the non-commutative field theory.1,2,3 This was achieved by the means of the twisted action of the Poincaré group on the tensor product of the fields. We investigate the consequences of this approach for the quantized fields.

Sign in / Sign up

Export Citation Format

Share Document