Recent progress on the description of relativistic spin: vector model of spinning particle and rotating body with gravimagnetic moment in General Relativity

TL;DR

This paper reviews recent vector models of relativistic spin, analyzing their classical and quantum properties, and applying them to understand spin interactions in gravitational and electromagnetic fields, clarifying longstanding issues.

Contribution

It develops a comprehensive vector model of relativistic spin and applies it to resolve key issues in spin dynamics within General Relativity and quantum mechanics.

Findings

Clarifies the relation between relativistic quantum mechanics and the Dirac equation.

Addresses spin-induced non-commutativity and covariant formalism.

Improves the behavior of equations describing rotating bodies in ultra-relativistic regimes.

Abstract

We review the recent results on development of vector models of spin and apply them to study the influence of spin-field interaction on the trajectory and precession of a spinning particle in external gravitational and electromagnetic fields. The formalism is developed starting from the Lagrangian variational problem, which implies both equations of motion and constraints which should be presented in a model of spinning particle. We present a detailed analysis of the resulting theory and show that it has reasonable properties on both classical and quantum level. We describe a number of applications and show how the vector model clarifies some issues presented in theoretical description of a relativistic spin: A) One-particle relativistic quantum mechanics with positive energies and its relation with the Dirac equation and with relativistic {\it Zitterbewegung}; B) Spin-induced non commutativity and the problem of covariant formalism; C) Three-dimensional acceleration consistent with coordinate-independence of the speed of light in general relativity and rainbow geometry seen by spinning particle; D) Paradoxical behavior of the Mathisson-Papapetrou-Tulczyjew-Dixon equations of a rotating body in ultra relativistic limit, and equations with improved behavior.