Spectator Composes a Gravitational Canon: Spectator-field-triggered Phase Transition During Inflation and its Anisotropic Gravitational Wave Signals

TL;DR

This paper introduces a framework where a spectator field triggers a phase transition during inflation, leading to anisotropic gravitational wave signals due to topological defects and quantum fluctuations modulating the transition timing.

Contribution

It presents a novel mechanism for generating anisotropic gravitational waves via spectator-field-triggered phase transitions during inflation.

Findings

Topological defects are inflated outside the horizon and reenter later, producing GW signals.

Quantum fluctuations modulate transition timing, creating large-scale anisotropies in GW background.

The framework can be applied to various spectator-modulated phenomena, including Higgs fields.

Abstract

We propose a general framework in which a phase transition is triggered during cosmic inflation by the slow-roll dynamics of a spectator field. The topological defects formed at the transition are inflated outside the horizon, reenter it after inflation, and can subsequently generate characteristic gravitational-wave (GW) signals. Quantum fluctuations of the spectator field modulate the timing of the transition, imprinting large-scale anisotropies in the resulting GW background. As an explicit realization, the spectator field may be identified with the Higgs field in a supersymmetric Standard Model. More generally, our framework applies to a wide class of spectator-modulated phenomena, providing a generic mechanism for producing anisotropic GW signals.