Dynamics of Symmetry Breaking and Tachyonic Preheating

TL;DR

This paper analyzes spontaneous symmetry breaking via tachyonic instabilities and introduces tachyonic preheating as an extremely efficient, nonperturbative mechanism. Using 3D lattice simulations, it demonstrates that symmetry breaking can complete within a single oscillation for both quadratic and cubic toy potentials, revealing domain and bubble dynamics and the limitations of perturbative approaches. The authors extend the analysis to hybrid inflation, showing that tachyonic preheating is a generic feature across F-term and D-term SUSY models, often terminating coherent inflaton oscillations after one cycle. These findings have broad implications for reheating, defect formation, gravitino production, and baryogenesis in cosmology and may inform heavy-ion collision phenomenology through disoriented chiral condensate scenarios.

Abstract

We reconsider the old problem of the dynamics of spontaneous symmetry breaking using 3d lattice simulations, and develop a theory of tachyonic preheating, which occurs due to the spinodal instability of the scalar field. Tachyonic preheating is so efficient that symmetry breaking typically completes within a single oscillation of the field distribution as it rolls towards the minimum of its effective potential. As an application of this theory we consider preheating in the hybrid inflation scenario, including SUSY-motivated F-term and D-term inflationary models. We show that preheating in hybrid inflation is typically tachyonic and the stage of oscillations of a homogeneous component of the scalar fields driving inflation ends after a single oscillation. Our results may also be relevant for the theory of the formation of disoriented chiral condensates in heavy ion collisions.

Figures (6)

• Figure 1: The process of symmetry breaking in the model (\ref{['aB1']}) for $\lambda = 10^{-4}$. In the beginning the distribution is very narrow. Then it spreads out and shows two maxima which oscillate about $\phi = \pm v$ with an amplitude much smaller than $v$. These maxima never come close to the initial point $\phi = 0$. The values of the field are shown in units of $v$.
• Figure 2: Growth of quantum fluctuations in the process of symmetry breaking in the quadratic model (\ref{['aB1']}).
• Figure 3: The process of symmetry breaking in the model (\ref{['aB1']}) for a complex field $\phi$. The field distribution falls down to the minimum of the effective potential at $|\phi| = v$ and experiences only small oscillations with rapidly decreasing amplitude $|\Delta\phi| \ll v$.
• Figure 4: Fast growth of the peaks of the distribution of the field $\phi$ in the cubic model (\ref{['cub']}). It should be compared with Fig. \ref{['onefieldslice']} for the quadratic model (\ref{['aB1']}).
• Figure 5: Histograms describing the process of symmetry breaking in the model (\ref{['cub']}) for $\lambda = 10^{-2}$. After a single oscillation the distribution acquires the form shown in the last frame and after that it practically does not oscillate.