Chiral plasma instability and primordial Gravitational wave

TL;DR

This paper explores how chiral plasma instabilities in the early universe can generate unique gravitational wave spectra, potentially detectable by future experiments like eLISA, linking high-temperature physics with observable cosmological signals.

Contribution

It introduces a novel mechanism for gravitational wave generation from chiral plasma instabilities caused by gravitational anomalies at high temperatures.

Findings

Generated gravitational waves have a unique spectrum.

Frequency range depends on the universe's temperature during generation.

Estimated amplitudes suggest potential detectability by future experiments.

Abstract

It is known that cosmic magnetic field, if present, can generate anisotropic stress in the plasma and hence, can act as a source of gravitational waves. These cosmic magnetic fields can be generated at very high temperature, much above electroweak scale, due to the gravitational anomaly in presence of the chiral asymmetry. The chiral asymmetry leads to instability in the plasma which ultimately leads to the generation of magnetic fields. In this article, we discuss the generation of gravitational waves, during the period of instability, in the chiral plasma sourced by the magnetic field created due to the gravitational anomaly. We have shown that such gravitational wave will have a unique spectrum. Moreover, depending on the temperature of the universe at the time of its generation, such gravitational waves can have a wide range of frequencies. We also estimate the amplitude and frequency of the gravitational waves and delineate the possibility of its detection by future experiments like eLISA.