We study the contribution to the QCD axion dark matter abundance that is produced by
string defects during the so-called scaling regime. Clear evidence of scaling violations is …

Axion stars are hypothetical objects formed of axions, obtained as localized and coherently
oscillating solutions to their classical equation of motion. Depending on the value of the field …

Oscillons are spatially localized, time-periodic, and long-lived configurations that were
primarily proposed in scalar field theories with attractive self-interactions. In this paper, we …

Numerical simulations show that a massive real scalar field in a nonlinear theory can form
long-lived oscillating localized states. For a self-interacting scalar on a fixed background …

We study the radio signals generated when an axion star enters the magnetosphere of a
neutron star. As the axion star moves through the resonant region where the plasma …

We discuss the unique phenomenology of first-order phase transitions catalyzed by
primordial black holes (BHs). If the number of BHs within one Hubble volume is smaller than …

Computing in Nonlinear Media and Automata Collectives presents an account of new ways
to design massively parallel computing devices in advanced mathematical models, such as …

A bstract We study I-balls/oscillons, which are long-lived, quasi-periodic, and spatially
localized solutions in real scalar field theories. Contrary to the case of Q-balls, there is no …

Strong numerical evidence is presented for the existence of a continuous family of time-
periodic solutions with “weak” spatial localization of the spherically symmetric nonlinear …

We present results from a study of the fine structure of oscillon dynamics in the 3+ 1
spherically symmetric Klein-Gordon model with a symmetric double-well potential. We show …