Arthur Kosowsky, University of Pittsburgh, is visiting us

Arthur Kosowsky is a theoretical physicist and cosmologist. He received his Ph.D. in Physics in 1994 from the University of Chicago and under the supervision of Michael Turner, where he was an NSF Graduate Research Fellow and a NASA GSRP fellow. He then held positions as a Junior Fellow at Harvard University and as assistant then associate professor at Rutgers, before moving to the University of Pittsburgh, where he is a Professor and was Chair of the Department of Physics and Astronomy. He was divisional associate editor for Physical Review Letters.

Arthur's research focuses on cosmology and related issues of theoretical physics. He has done extensive work on the theory of the cosmic microwave background (CMB) radiation and the ways in which it constrains our models of the Universe. He is interested in possible extensions or modifications to the standard cosmological model, and observational tests which can distinguish particular alternatives from the standard cosmology. The standard model of cosmology strongly suggests that the Universe underwent a period of exponential expansion, known as inflation, in its first moments. Inflation naturally explains why the Universe is spatially (almost) flat, highly isotropic, and lacking in magnetic monopoles from grand-unified symmetry breaking to the standard model of particle physics. It also provides a mechanism for generating small density perturbations in the Universe, which have Gaussian random statistics, a power spectrum nearly but not quite scale invariant, and with equal fractional perturbations in all matter components. To a very good approximation, this is what our Universe looks like. However, we have no realistic physical theory of inflation, and phenomenological models based on a classical scalar field with some specified potential lack a clear physical interpretation and require finely-tuned initial conditions. Arthur is interested in constructing more realistic models, based on known properties of quantum fields in curved spacetimes, which explain how inflation began, the mechanism fueling the inflationary expansion, and the dynamical evolution of the Universe throughout the inflationary epoch. He also has a long-standing interest in a stochastic background of gravitational waves from possible phase transitions in the early Universe, and is additionally interested in observations which are, to some extent, unexpected in the standard cosmological model, particularly "anomalies" in the microwave sky. 

Arthur was elected a fellow of the American Physical Society in 2014 for "landmark contributions to cosmology, including pioneering work on the use of CMB fluctuations for precision cosmology and pioneering work on the origin and detection of primordial gravitational waves." In addition to his theoretical research, he collaborates on observational work through the Atacama Cosmology Telescope and Simons Observatory (of which he is the current Collaboration Spokesperson).