College of Arts and Sciences

This talk will describe some experiences gained in starting and growing two optical companies, WYKO Corporation (1984-1997) and 4D Technology (2002-present). Both companies designed, manufactured, and sold computerized interferometric systems for the measurement of surface shape and surface roughness. Founding, growing, and cashing out of WYKO was an unbelievable experience that was more fun than I ever dreamed anything could be. It was so much fun I felt I had to do it again. Both the fun parts and the not so fun parts for both WYKO and 4D will be discussed. The biggest surprises experienced and what I think are the most important factors in growing a successful high-tech company will be described.

Continue reading… Some Experiences Gained in Starting and Growing Optical Companies – James C. Wyant

Granular materials such as sand or rice grains behave in ways that are often counterintuitive. An example is “footprints on sand” which owe their origin to a phenomenon known as dilatancy. Our intuition often fails because dry granular materials are non-cohesive, and live at zero temperature. The distinction between gases, liquids and solids is ill understood. These materials can solidify via non-equilibrium pathways in which applied stresses or boundary constraints play a crucial role. A striking example of this is shear-jamming, where an amorphous granular solid is created through the application of shear. This is in sharp contrast to our usual experience of shearing leading to flow.

Continue reading… Origin of rigidity in granular solids – Bulbul Chakraborty

On July 4th 2012 physicists working at the Large Hadron Collider (LHC), the world’s highest-energy proton accelerator, at CERN in Geneva, Switzerland announced the discovery of a new particle that is about 135 times heavier than a proton. This particle seems to closely resemble the Higgs boson that was hypothesized over forty years ago to explain the masses of all elementary particles in the universe. In this talk, I will summarize the context for this discovery and present the latest studies to elucidate the properties of this Higgs-like particle. I will conclude by discussing prospects for future measurements of this particle that will be allowed by the energy and luminosity upgrade of the LHC.

Continue reading… The discovery of a new particle. Is it the Higgs? – Daniela Bortoletto

In this talk, I will review our studies of photonic nanostructures of random morphology. First, I show how we can trap light in such structures to make random lasers. Next, learning from the non-iridescent color generation by isotropic nanostructures in bird feathers, we use short-range order to enhance light confinement and improve lasing efficiency in artificial nanostructures. Finally I will introduce our recent work on time-reversed laser – coherent perfect absorber.

Continue reading… Random laser, bio-inspired laser, and time-reversed laser – Hui Cao

It has been known for some time that a system with a filled band will have an integer quantum Hall conductance equal to its Chern number, a toplogical index associated with the band. While this is true for a system in a magnetic field with filled Landau Levels, even a system in zero external field can exhibit the QHE if its band has a Chern number. I review this issue and discuss a more recent question of whether a partially filled Chern band can exhibit the Fractional QHE. I describe the work done with Ganpathy Murthy in which we show how composite fermions,

Continue reading… Hamiltonian Theory of Fractional Chern Bands – R. Shankar

Molecular interactions determine, for example, how transcription factors recognize their DNA binding sites, how proteins interact with each other, and consequently how a biological system functions. Since both proteins and DNAs are significantly charged, electric interactions are among the most important when studying biomolecular interactions. Despite a long history of research of complex systems such as biomolecules in solvent, these problems remain difficult even at the level of classical electrostatics and call for new schemes with controllable accuracy. When one wishes to study short range effects that require quantum mechanics, quantitative understanding is hindered by the presence of many electrons.

Continue reading… Molecular interactions: linking physics and biology – Yi-Kuo Yu

A longstanding issue in attempts to understand the Everett (Many-Worlds) approach to quantum mechanics is the origin of the Born Rule: why is the probability given by the square of the amplitude? Recently, Page has raised another puzzle: the Born Rule itself is insufficient in cases where the wave function includes multiple indistinguishable observers in the same branch. We argue that both problems share a common solution, arising from a proper treatment of self-locating uncertainty (physical situations containing multiple copies of identical observers). This analysis gives a simple, physics-oriented derivation of the Born Rule, as well as a justification for the treatment of identical classical observers.

Continue reading… Many Worlds, the Born Rule, and Self-Locating Uncertainty – Sean Carroll

Contact charging occurs when two materials are brought into contact and then are separated. As a result of the contact, charge is transferred such that one material becomes charged positively and the other becomes charged negatively. Everyone is familiar with this effect, even children who have ‘experimented’ by rubbing a balloon on their hair and seeing the balloon and hair become highly charged. But which material charges positively and which charges negatively? The answer to this simple question is not really known. In contrast to the tremendous progress in most fields of science, the understanding of contact charging is not much better now than it was 2500 years ago.

Continue reading… Electrostatic charging of flowing granular materials – Dan Lacks

Three 15-minute talks on the 2012 Nobel prizewinners and their work. The 2012 Nobel Prize in Physics: Making Gedanken Experiments Real.The 2012 Nobel Prize in Physics was awarded to Serge Haroche and David Wineland for experimental methods that allow the measurement and manipulation of individual quantum systems. I will briefly describe their complementary experimental methods, their ground breaking experiments, and possible implications for clocks, computers and cats. The 2012 Nobel Prize in Chemistry Award to Robert Lefkowitz and Brian Kobilka: G Protein-Coupled Receptors as Key Mediators of Biological Communication and Regulation A fundamental aspect of biological regulation is that cells can sense many types of changes in their external environment and respond to these extrinsic cues with appropriate functional adaptation in their internal biochemistry.

Continue reading… The 2012 Science Nobel Prizes – What were they given for? – George Dubyak (Physiology and Biophysics), Paul Tesar (Genetics), Harsh Mathur (Physics)

The deformation of many solid and granular materials is not continuous, but discrete, with intermittent slips similar to earthquakes. Here, we suggest that the statistical distributions of the slips, such as the slip-size distributions and their cutoffs, all follow approximately the same regular (power-law) functions for systems spanning 13 decades in length, from tens of nanometers to hundreds of kilometers; for compressed nano-crystals, amorphous materials, sheared granular materials, lab-sized rocks, and earthquakes. The similarities are explained by a simple analytic model, which suggests that results are transferable across scales. This study provides a unified understanding of fundamental properties of shear-induced deformation in systems ranging from nanocrystals to earthquakes.

Continue reading… Unifying theory for universal quake statistics: from compressed nanopillars to earthquakes – Karin Dahmen

One of the most puzzling paradoxes in philosophy, mathematics and finance is the two-envelope paradox (http://en.wikipedia.org/wiki/Two_envelopes_problem). It is many years old, but it still generates 5-10 publications each year as many disciplines each have their own viewpoints and methods of attack. Consider two sealed envelopes, one of which contains twice as much money as the other. You get to pick one and keep the amount inside. You pick one and reason thusly, “My envelope contains an amount which I’ll define as X. The other envelope must contain one-half X or twice X with a 50 percent chance of either. So the average value in the other envelope is 1.25 X.

Continue reading… The Two-Envelope Paradox – Edwin Meyer

Several years ago, Howard Georgi introduced the concept of unparticles. Unparticle stuff has no particular mass. In fact, the mass of unparticle stuff looks the same on any number of scales in contrast to particle matter which has a definite mass. Another curious fact is that unparticles can carry current but make no contribution to the density of particles. In strongly correlated electron matter such as the high-temperature superconductors, the number of charge carriers that has a particle interpretation is less than the conserved charge. I will argue that unparticle stuff makes up the difference. The consequences of unparticle stuff for the physics of high-temperature superconductors will be explored.

Continue reading… Unparticles in Strongly Correlated Electron Matter – Philip Phillips