RESUMO
We show that simulations of magnetohydrodynamic turbulence in the multiphase interstellar medium yield an E/B ratio for polarized emission from Galactic dust in broad agreement with recent Planck measurements. In addition, the B-mode spectra display a scale dependence that is consistent with observations over the range of scales resolved in the simulations. The simulations present an opportunity to understand the physical origin of the E/B ratio and a starting point for more refined models of Galactic emission of use for both current and future cosmic microwave background experiments.
RESUMO
We propose a new approach for the calculation of the spectrum of excitations of QCD flux tubes. It relies on the fact that the worldsheet theory is integrable at low energies. With this approach, energy levels can be calculated for much shorter flux tubes than was previously possible, allowing for a quantitative comparison with existing lattice data. The improved theoretical control makes it manifest that existing lattice data provides strong evidence for a new pseudoscalar particle localized on the QCD flux tube--the worldsheet axion.
RESUMO
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. This set includes both string monodromy models and a class of supergravity inspired scenarios and is in good agreement with the current central values of the concordance cosmology parameters. We assume that the inflaton is weakly coupled to other fields so as not to quickly drain energy from the oscillons or prevent them from forming. An oscillon-dominated universe has a greatly enhanced primordial power spectrum on very small scales relative to that seen with a quadratic potential, possibly leading to novel gravitational effects in the early Universe.