A Lower Bound on Dark Matter Mass.

We argue that there is a lower bound of order 10^{-19}  eV on dark matter mass if it is produced after inflation via a process with finite correlation length. We rely on nondetection of free-streaming suppression and white-noise enhancement of density perturbations as the observational inputs.

Integrator for general spin-s Gross-Pitaevskii systems.

We provide an algorithm, i-SPin 2, for evolving general spin-s Gross-Pitaevskii or nonlinear Schrödinger systems carrying a variety of interactions, where the 2s+1 components of the "spinor" field represent the different spin-multiplicity states. We consider many nonrelativistic interactions up to quartic order in the Schrödinger field (both short and long range, and spin-dependent and spin-independent interactions), including explicit spin-orbit couplings. The algorithm allows for spatially varying external and/or self-generated vector potentials that couple to the spin density of the field.

First Star-Forming Structures in Fuzzy Cosmic Filaments.

In hierarchical models of structure formation, the first galaxies form in low-mass dark matter potential wells, probing the behavior of dark matter on kiloparsec scales. Even though these objects are below the detection threshold of current telescopes, future missions will open an observational window into this emergent world. In this Letter, we investigate how the first galaxies are assembled in a "fuzzy" dark matter (FDM) cosmology where dark matter is an ultralight ∼10^{-22}  eV boson and the primordial stars are expected to form along dense dark matter filaments.

Equation of State and Duration to Radiation Domination after Inflation.

We calculate the equation of state after inflation and provide an upper bound on the duration before radiation domination by taking the nonlinear dynamics of the fragmented inflaton field into account. A broad class of single-field inflationary models with observationally consistent flattening of the potential at a scale M away from the origin, V(ϕ)∝|ϕ|^{2n} near the origin, and where the couplings to other fields are ignored, is included in our analysis. We find that the equation of state parameter w→0 for n=1 and w→1/3 (after sufficient time) for n≳1.

Clash of kinks: phase shifts in colliding nonintegrable solitons.

We derive a closed-form expression for the phase shift experienced by (1+1)-dimensional kinks colliding at ultrarelativistic velocities (γv>>1), valid for arbitrary periodic potentials. Our closed-form expression is the leading-order result of a more general scattering theory of solitary waves described in a related paper [Phys. Rev.

Oscillons after inflation.

Oscillons are massive, long-lived, localized excitations of a scalar field. We show that in a class of well-motivated single-field models, inflation is followed by self resonance, leading to copious oscillon generation and a lengthy period of oscillon domination. These models are characterized by an inflaton potential which has a quadratic minimum and is shallower than quadratic away from the minimum.