Guest Alumni Speakers

Professor Laszlo Barabasi (University of Notre Dame)

Abstract Title: Complex Networks: From the Web to Human Diseases

Networks with complex topology describe systems as diverse as the cell or the World Wide Web. The emergence of these networks is driven by self-organizing processes that are governed by simple but generic laws. I will show that cells and complex man-made networks, such as the Internet, the world wide web, as well as social networks share the same large-scale topology, and discuss the consequences of their structure on the robustness of various systems against failures and attacks, with implications to drug design, diseases, and our ability to understand the function of the complex systems around us.

Dr. Eli Ben-Naim (Los Alamos National Laboratory)

Abstract Title: Energy Distributions in Granular Media

Energy dissipation through inelastic collisions puts granular materials out of equilibrium. To balance this dissipation one must constantly inject energy to keep the system in motion. This talk will highlight the statistical mechanics of driven granular gases that includes anomalies such as sub-exponential and even power-law energy distributions, singular energy distributions, correlation between different degrees of freedom, and breakdown of energy equipartition between translational and rotational modes.

Professor Maxwell Chertok (University of California, Davis)

Abstract Title: From T-Violation to Taus and Trileptons: Searching for Exotics in Hadron Collisions

The next few years of running and analysis of the Tevatron data will either produce some bona fide excitement of its own, or at least serve as ideal preparation for the Large Hadron Collider era. After a brief introduction to high energy physics, I will give an overview of the Tevatron program for new phenomena searches, with a focus on multilepton signatures including the tau. I will give highlights of the LHC machine and detectors and present some preliminary studies relevant to the search for exotics.

Dr. Michael J. Manfra (Bell Labs, Alcatel-Lucent)

Abstract Title: Two-dimensional semiconductor systems: from the transistor to the fractional quantum Hall Effect

Semiconductor heterostructures form the basis for many of our modern technologies, ranging from the transistor to the laser diode. They also provide an ideal playground for exploring the physics of interacting electrons in two dimensions. In this talk I will try to describe the weird and fascinating behavior exhibited by two-dimensional electrons in semiconductor heterostructures when they are subjected to a large perpendicular magnetic field at low temperatures. In a magnetic field, the density of states of a two-dimensional electron gas is transformed into a series of discrete, highly degenerate, states known as Landau levels (LLÕs). At high fields, all of the electrons can be accommodated within a single LL known as the lowest LL. In this limit, the kinetic energy of the electrons is quenched and the energy spectrum of the system is determined solely by the mutual interactions of the many electrons. The strong interactions of the electrons in the lowest LL produce a series of collective states known as the fractional quantum Hall effect (FQHE). The FQHE is distinguished in electron transport measurements by a vanishing of the longitudinal resistance and quantization of the transverse, or Hall, resistance when the occupancy of the lowest LL takes on certain fractional values. At lower magnetic fields, when more than one Landau level is occupied, the FQHE competes with other highly correlated ground states. These novel ground states, distinct from the FQHE, produce their own unique signatures in transport measurements. Understanding the physics of excited Landau levels is presently an area of intense research. It is my hope that this talk will give you a flavor for both fundamental and technological aspects of this exciting field.

Professor Mark Messier (Indiana University)

Abstract Title: Chasing the Ghost Particle : Experimental searches for neutrino mass and mixing

Recent measurements indicate that the elusive neutrino may have enough mass to make its contribution to the total mass of the universe comparable to the total mass of the stars and planets. Currently, there is a vigorous experimental program to further probe the properties of the neutrino using a phenomenon called neutrino oscillations by which a neutrino changes its identity in flight from source to detector. Ultimately experimenters hope to find evidence that this oscillation is different for neutrinos than it is for anti- neutrinos. This matter/anti-matter difference may help explain why more matter survived the Big Bang than anti-matter. In this talk I will give an overview of this experimental program, focusing on my own work at the Fermilab National Accelerator Laboratory.

Professor Mike Naughton (Boston College)

Abstract Title: Electron motion in quasi-one dimensional conductors

Frohlich, in an attempt to explain the conundrum that was superconductivity, proposed in 1954 a new type of a electron motion in one-dimensional insulators using electron-phonon coupling, much like BCS would a few years later. This was academic at the time, because neither 1D insulators nor superconductors existed. A year later, Peierls taught us that even a 1D metal is unstable at finite temperature. Again, an academic exercise, since 1D metals didn’t exist either. Strictly speaking, neither of these exotic entities exists yet today, but there are real materials that are very close,
structurally and electronically. Not surprisingly, many surprises have emanated from these so-called quasi-1D conductors, which allow us a window into the world of electrons confined to less than three dimensions, rather relevant in today’s nano-frontier. This talk will highlight one class of materials that can be tuned to be insulating, semiconducting, metallic, superconducting, magnetic, nonmagnetic, etc. (all in the same day), a direct result of Frohlich, Peierls, and their quasi-1D nature.

Professor Sharon Glotzer (University of Michigan)

Abstract Title: Exploiting anisotropy for self-assembly of nanoparticles and colloids: The shape(s) of things to come

Recent breakthroughs in particle synthesis leading to nanoscopic and colloidal particles of unusual shape and patterning have paved the way for a revolution in materials formed from the self-assembly of these building blocks. The unprecedented anisotropy of today’s new nanoparticle and colloidal building blocks starkly contrasts with the isotropic, spherical colloids that have been the focus of particle assembly for more than a generation. As the materials community gains further control over the design and fabrication of these new particles, they are poised to become the “atoms” and “molecules” of tomorrow’s materials and devices, provided we can learn to assemble them into predictable and useful structures. No general theory exists to predict the range of structures possible for these new building blocks as a function of thermodynamic conditions, and the complementary problem of inverse design of a particular building block that can self-assemble into a desired target structure is difficult with as yet no standard design algorithm. In this talk, we present a conceptual framework with which to describe these new building blocks and explore their assembly properties. We present results of computer simulations of nanoparticle design and assembly. We show how various measures of anisotropy, including particle shape, patterning, functionalization and interaction selectivity, can be combined and exploited to achieve complex mesoscale one-, two- and three-dimensional structures such as wires, sheets, virus-like shells and colloidal “molecules”, diamond arrays, icosahedra, gyroid, chiral cylinders, and other complex structures through self-assembly.