Density Perturbations in Chain Inflation

We consider the model of ``Chain Inflation,'' in which the period of inflation in our universe took the form of a long sequence of quantum tunneling events. We find that in the simplest such scenario, in which the tunneling processes are uniform, approximately 10^4 vacua per e-folding of inflation are required in order that the density perturbations produced are of an acceptable size. We arrive at this conclusion through a combination of analytic and numerical techniques, which could also serve as starting points for calculations with more general sets of assumptions.Comment: 28 pages, 16 figures; v2: corrected typos, increased resolution on D=2+1 data point

Hawking Radiation in the Ghost Condensate is Non-Thermal

We consider a Schwarzschild black hole immersed in a ghost condensate background. It is shown that the Hawking radiation in the quanta of small perturbations around this background is highly suppressed- in particular it is not given by a thermal spectrum. This result is in accord with observations that such black holes can be used to violate the generalized second law of thermodynamics, and thus cannot have a standard entropy/area relation.Comment: 26 pages; v2: reference added, missing Christoffel symbols included in appendix, minor typos corrected in equations (39) and (50

Pure Gravity Mediation of Supersymmetry Breaking at the LHC

Supersymmetric theories which can allow for a 125 GeV Higgs mass and also solve the naturalness and susy flavor problems now require a fair degree of complexity. Here we consider the simplest possibility for supersymmetry near the weak scale, but with the requirement of naturalness dropped. In "pure gravity mediation", all supersymmetric particles except for the gauginos lie at tens to thousands of TeV, with the gauginos obtaining loop suppressed masses automatically by anomaly mediation and higgsino threshold corrections. The gauginos are the lightest superpartners, and we investigate the current collider constraints on their masses, as well as the future reach of the LHC. We consider gluino pair production with a jets + missing energy signature, as well as events with disappearing charged tracks caused by charged winos decaying into their neutral partners. We show that presently, gluino masses less than about 1 TeV and wino masses less than about 300 GeV are excluded, and that the 14 TeV LHC can probe gluino masses up to about 2 TeV and wino masses up to 1 TeV.Comment: 22 pages, 5 figure