http://arxiv.org/abs/2010.07789
Oscillons are spatially localized structures that appear in scalar field theories and exhibit extremely long life-times. We go beyond single-field analyses and study oscillons comprised of multiple interacting fields, each having an identical potential with quadratic, quartic and sextic terms. We consider quartic interaction terms of either attractive or repulsive nature. In the two-field case, we construct semi-analytical oscillon profiles for different values of the potential parameters and coupling strength using the two-timing small-amplitude formalism. We show that the interaction sign, attractive or repulsive, leads to different oscillon solutions, albeit with similar characteristics, like the emergence of “flat-top” shapes. In the case of attractive interactions, the oscillons can reach higher values of the energy density and smaller values of the width. For repulsive interactions we identify a threshold for the coupling strength, above which oscillons do not exist within the two-timing small-amplitude framework. We extend the Vakhitov-Kolokolov (V-K) stability criterion, which has been used to study single-field oscillons, and show that the symmetry of the potential leads to similar equations as in the single-field case, albeit with modified terms. We explore the basin of attraction of stable oscillon solutions numerically to test the validity of the V-K criterion and show that, depending on the initial perturbation size, unstable oscillons can either completely disperse or relax to the closest stable configuration. Similarly to the V-K criterion, the decay rate and lifetime of two-field oscillons are found to be qualitatively and quantitatively similar to their single-field counterparts. Finally, we generalize our analysis to multi-field oscillons and show that the governing equations for their shape and stability can be mapped to the ones arising in the two-field case.
F. Dissel and E. Sfakianakis
Thu, 28 Jan 21
5/64
Comments: 30 pages, 8 figures