The 11th Annual Pappalardo Fellowships
in Physics Symposium

Howard Messing '73 (Course VI), President & CEO, Meditech, Inc.

Dissecting the Remnants of Nearby Supernova Explosions

Supernovae are the explosive ends of the lives of massive stars. They are the most energetic events in the Universe, and they produce almost all the elements in the periodic table. Although several hundreds of supernovae are found each year by dedicated robotic telescopes, these explosions are too far away to study their physics in detail. I will discuss how we can study the remnants left over from supernova explosions in our own Milky Way galaxy in order to probe the nature of the explosions and their effects on surrounding space.

New Physics Sandwiched Between Two Oxide Insulators

The continuous search for novel electronic and spintronic devices recently came to fruition in the form of oxide interfaces. Combining two boring oxide insulators can result in an unexpected highly-conducting layer at the interface. At present, similar conducting layers are used with great success in silicon-based computer chips. However, the oxide interfaces exhibit a much larger variety of phenomena, which may lead to additional applications, particularly in the field of spintronics. Most strikingly, oxide interfaces can simultaneously be superconducting and ferromagnetic. Coexistence of ferromagnetism and superconductivity is surprising, since these phenomena usually destroy each other. We constructed a model of the electronic structure of the oxide interfaces that explains their unusual properties. In particular, we find that in order to survive the harmful effects of ferromagnetism, the superconductor is substantially different from conventional ones.

The Disappearing Neutrino?

More than 80 years after its proposed existence, the neutrino remains mysterious and enigmatic. We don't know the mass of the neutrino, how many neutrinos there are, if neutrinos are different than anti-neutrinos, and more. I will describe one of the neutrino's most interesting properties, referred to as "oscillation" or "mixing," and our attempts to understand it. Specifically, I will discuss Double Chooz, a nuclear reactor-based neutrino oscillation experiment and its pursuit of the last mixing angle.

A Membrane Puzzle

It has been known for quite some time that ten-dimensional string theory is contained within a fairly mysterious eleven-dimensional theory of membranes (higher dimensional generalizations of strings) called M-theory. Both string theory and M-theory exhibit a duality where, in specific scenarios, quantum physics and gravity provide different points of view on the very same properties of a system. I will explain how in using this duality one can shed light onto a puzzling aspect of the physics of the M-theory membranes.

Testing Galaxy Formation Models at the Small Scales

The distribution of masses of dwarf satellite galaxies that are observed around Local Group galaxies differs substantially from simulations based on cold dark matter--the simulations predict many more dwarf galaxies than are seen. The Local Group, however, may be anomalous in this
regard. The lack of visible stars and gas severely limits the possibility of detecting these satellites in other galaxies. I will show how gravitational lensing can address this issue in a unique way by detecting low-mass satellites at cosmological distances independently of their luminosity. I will present the discovery of two small-mass dark satellites in very distant galaxies and discuss their implication for galaxy formation models.