Gravitational Radiation Generated by Cosmological Phase Transition Magnetic Fields

TL;DR

This work links fundamental particle physics phase-transition dynamics to observable gravitational waves by deriving magnetic fields from MSSM and QCD Lagrangians and propagating them through a non-helical MHD turbulence model. The authors compute the resulting GW spectrum, finding that electroweak-transition–driven turbulence can yield a peak around 1 mHz with amplitudes potentially detectable by LISA, while QCD-transition–driven signals fall far below LISA's bands. The analysis highlights the role of the Alfvén velocity and turbulence decorrelation in shaping the GW signal and provides a framework for connecting early-Universe magnetogenesis to GW observables. Overall, the paper suggests that future space-based detectors could probe magnetic-field–driven GWs from EW-scale physics, offering a window into cosmological phase transitions and MSSM dynamics.

Abstract

We study gravitational waves generated by the cosmological magnetic fields induced via bubble collisions during the electroweak (EW) and QCD phase transitions. The magnetic field generation mechanisms considered here are based on the use of the fundamental EW minimal supersymmetric (MSSM) and QCD Lagrangians. The gravitational waves spectrum is computed using a magnetohydrodynamic (MHD) turbulence model. We find that gravitational wave spectrum amplitude generated by the EW phase transition peaks at frequency approximately 1-2 mHz, and is of the order of $10^{-20}-10^{-21}$; thus this signal is possibly detectable by Laser Interferometer Space Antenna (LISA). The gravitational waves generated during the QCD phase transition, however, are outside the LISA sensitivity bands.

Figures (1)

• Figure 1: $h_C(f)$ for the EWPT with $g_* = 100$, $v_b=1/2$, and $v_0=v_A$ with zero magnetic helicity. The top panel: $T_* = 80$ GeV, (solid line), $T_*= 100$ GeV (dash line), and $T_\star=150$ GeV (dash-dot line) with $\beta=100H_\star$, while $T_\star=100$ GeV and $\beta = 50H_\star$ (solid line), $\beta=100 H_\star$ (dash line), and $\beta=150H_\star$ (dash-dot line) in the bottom panel. In both panels the bold solid line corresponds to the 1-year, $5\sigma$ LISA design sensitivity curve curve including confusion noise from white dwarf binaries, bold dash line whitedwarfs.