Assembly of supermassive black hole seeds

We present a suite of six fully cosmological, three-dimensional simulations of the collapse of an atomic cooling halo in the early Universe. We use the moving-mesh code arepo with an improved primordial chemistry network to evolve the hydrodynamical and chemical equations. The addition of a strong Lyman-Werner background suppresses molecular hydrogen cooling and permits the gas to evolve nearly isothermally at a temperature of about 8000 K. Strong gravitational torques effectively remove angular momentum and lead to the central collapse of gas, forming a supermassive protostar at the center of the halo. We model the protostar using two methods: sink particles that grow through mergers with other sink particles, and a stiff equation of state that leads to the formation of an adiabatic core. We impose threshold densities of $10^8$, $10^{10}$, and $10^{12}\,\text{cm}^{-3}$ for the sink particle formation and the onset of the stiff equation of state to study the late, intermediate, and early stages in the evolution of the protostar, respectively. We follow its growth from masses $\simeq 10\,\text{M}_\odot$ to $\simeq 10^5\,\text{M}_\odot$, with an average accretion rate of $\langle\dot{M}_\star\rangle \simeq 2\,\text{M}_\odot\,\text{yr}^{-1}$ for sink particles, and $\simeq 0.8 - 1.4\,\text{M}_\odot\,\text{yr}^{-1}$ for the adiabatic cores. At the end of the simulations, the HII region generated by radiation from the central object has long detached from the protostellar photosphere, but the ionizing radiation remains trapped in the inner host halo, and has thus not yet escaped into the intergalactic medium. Fully coupled, radiation-hydrodynamics simulations hold the key for further progress.Comment: Matches accepted version. A video of the simulations can be found at https://vimeo.com/26883591

Correlated photon pairs generated from a warm atomic ensemble

We present measurements of the cross-correlation function of photon pairs at 780 nm and 1367 nm, generated in a hot rubidium vapor cell. The temporal character of the biphoton is determined by the dispersive properties of the medium where the pair generation takes place. We show that short correlation times occur for optically thick samples, which can be understood in terms of off-resonant pair generation. By modifying the linear response of the sample, we produce near-resonant photon pairs, which could in principle be used for entanglement distribution

SB 106 - Patients First Act

The Patients First Act amends both Title 49 and Title 33 of the Official Code of Georgia Annotated, which allows the state to apply for two federal waivers. One being the Section 1115 waiver to the Social Security Act. The second being the Section 1332 waiver to the Affordable Care Act. Section 1115 waivers apply to Medicaid and may be sought to include a maximum income threshold up to 100% of the Federal Poverty Level. The Section 1332 innovation waiver applies to insurance coverage generally

A dramatic isotope effect in the reaction of ClSiH with trimethylsilane-1-d: experimental evidence for intermediate complexes in silylene Si-H(D) insertion reactions

A kinetic isotope effect (kD/kH) of 7.4 has been found for the reaction of chlorosilylene with trimethysilane (Me3SiD vs Me3SiH). Such a value can be accounted for by theoretical modelling, but only if an internal rearrangement of the initially form complex is included in the mechanism. This provides the first concrete evidence for such complexes