Small amplitude quasi-breathers and oscillons

TL;DR

This paper analyzes small amplitude quasi-breathers in scalar field theories, revealing a universal elliptic PDE and a critical dimension at D=4, and shows their effectiveness as initial data for long-lived oscillons.

Contribution

It derives a universal elliptic PDE for small amplitude quasi-breathers in scalar theories and identifies a critical dimension where they cease to exist.

Findings

Existence of a universal elliptic PDE for small amplitude QB's.

Critical dimension D=4 beyond which QB's do not exist.

QB's serve as effective initial data for long-lived oscillons.

Abstract

Quasi-breathers (QB) are time-periodic solutions with weak spatial localization introduced in G. Fodor et al. in Phys. Rev. D. 74, 124003 (2006). QB's provide a simple description of oscillons (very long-living spatially localized time dependent solutions). The small amplitude limit of QB's is worked out in a large class of scalar theories with a general self-interaction potential, in $D$ spatial dimensions. It is shown that the problem of small amplitude QB's is reduced to a universal elliptic partial differential equation. It is also found that there is the critical dimension, $D_{crit}=4$, above which no small amplitude QB's exist. The QB's obtained this way are shown to provide very good initial data for oscillons. Thus these QB's provide the solution of the complicated, nonlinear time dependent problem of small amplitude oscillons in scalar theories.