The Structure of the Oscillon: The Dynamics of Attractive Self-Interaction

Real scalar fields with attractive self-interaction may form self-bound states, called oscillons. These dense objects are ubiquitous in leading theories of dark matter and inflation; of particular interest are long-lived oscillons which survive past $14$ Gyr, offering dramatic astrophysical signatures into the present day. We introduce a new formalism for computing the properties of oscillons with improved accuracy, which we apply to study the internal structure of oscillons and to identify the physical mechanisms responsible for oscillon longevity. In particular, we show how imposing realistic boundary conditions naturally selects a near-minimally radiating solution, and how oscillon longevity arises from its geometry. Further, we introduce a natural vocabulary for the issue of oscillon stability, which we use to predict new features in oscillon evolution. This framework allows for new efficient algorithms, which we use to address questions of whether and to what extent long-lived oscillons are fine-tuned. Finally, we construct a family of potentials supporting ultra-long-lived oscillons, with lifetimes in excess of $10^{17}$ years.