Gravitational waves at the first post-Newtonian order with the Weyssenhoff fluid in Einstein-Cartan theory

TL;DR

This paper investigates gravitational wave generation from spinning fluids in Einstein-Cartan theory at the first post-Newtonian order, focusing on binary neutron star systems using a point-particle approximation.

Contribution

It extends the post-Newtonian formalism to include Weyssenhoff fluids with quantum spin in Einstein-Cartan theory, analyzing inspiralling binaries.

Findings

Derived gravitational wave expressions for Weyssenhoff fluids.

Applied formalism to binary neutron star systems.

Provided insights into spin effects in gravitational wave emission.

Abstract

The generation of gravitational waves from a post-Newtonian source endowed with a quantum spin, modeled by the Weyssenhoff fluid, is investigated in the context of Einstein-Cartan theory at the first post-Newtonian level by resorting to the Blanchet-Damour formalism. After having worked out the basic principles of the hydrodynamics in Einstein-Cartan framework, we study the Weyssenhoff fluid within the post-Newtonian approximation scheme. The complexity of the underlying dynamical equations suggests to employ a discrete description via the point-particle limit, a procedure which permits the analysis of inspiralling spinning compact binaries. We then provide a first application of our results by considering binary neutron star systems.