Formation of caustics in Dirac-Born-Infeld type scalar field systems

TL;DR

This paper studies how caustics form in Dirac-Born-Infeld scalar fields with various potentials, revealing conditions under which caustics appear or are avoided in different spacetime backgrounds.

Contribution

It analyzes caustic formation in DBI scalar fields for specific potentials, highlighting differences between Minkowski and FRW spacetimes.

Findings

Caustics form in inverse power-law potentials in Minkowski space.

No caustics in exponentially increasing potentials.

Caustic formation depends on spacetime background and potential type.

Abstract

We investigate the formation of caustics in Dirac-Born-Infeld type scalar field systems for generic classes of potentials, viz., massive rolling scalar with potential, $V(\phi)=V_0e^{\pm \frac{1}{2} M^2 \phi^2}$ and inverse power-law potentials with $V(\phi)=V_0/\phi^n,~0<n<2$. We find that in the case of\texttt{} exponentially decreasing rolling massive scalar field potential, there are multi-valued regions and regions of likely to be caustics in the field configuration. However there are no caustics in the case of exponentially increasing potential. We show that the formation of caustics is inevitable for the inverse power-law potentials under consideration in Minkowski space time whereas caustics do not form in this case in the FRW universe.