Axion miniclusters made easy

Axion miniclusters and Bose stars.

Evolution of inhomogeneities in the axion field around the QCD epoch is studied numerically, including for the first time important nonlinear effects. It is found that perturbations on scales corresponding to causally disconnected regions at T ∼ 1GeV can lead to very dense axion clumps, with present density ρa > ∼ 10 g cm. This is high enough for the collisional 2a → 2a process to lead to Bose–...

Femtolensing and Picolensing by Axion Miniclusters

Non-linear effects in the evolution of the axion field in the early Universe may lead to the formation of gravitationally bound clumps of axions, known as “miniclusters.” Minicluster masses and radii should be in the range Mmc ∼ 10M⊙ and Rmc ∼ 10cm, and in plausible early-Universe scenarios a significant fraction of the mass density of the Universe may be in the form of axion miniclusters. If s...

Atom Bomb Made Easy

Concurrent Programming Made Easy

The task of programming concurrent systems is substantially more difficult than the task of programming sequential systems with respect to both correctness and efficiency. In this paper we describe a constraint-based methodology for writing concurrent applications. A system is modeled as: (a) a set of processes containing a sequence of “markers” denoting the processes points of interest; and (b...

Distributed CQL Made Easy

This talk is about making it easy to implement a distributed CQL. CQL is a continuous query language that extends SQL with a notion of windows over infinite streams of data. Programmers like using CQL, because its syntax is already familiar to them from their experience with other database-backed applications. CQL was originally designed to target a single node implementation of the Stanford St...