College of Arts and Sciences

The homotopy theory of topological defects in ordered media fails to completely characterize systems with broken translational symmetry. I will demonstrate that the topological problem can be transformed into a geometric problem in one higher dimension. Fortunately, for two-dimensional smectics this amounts to the theory of surfaces in three space! Our work suggests natural generalizations of the two-dimensional smectic theory to higher dimensions and to crystals.

Continue reading… Smectics! – Randall Kamien

Physicists are constantly on the lookout for new symmetries in the ground states of quantum systems. Familiar examples include ferromagnets, which break spin-rotation symmetry, and superconductors, which break gauge symmetry. When a superconductor (S) and a ferromagnet (F) are put into contact with each other, interesting things happen, and the combined S/F hybrid system exhibits altogether new properties. There is a proximity effect where pair correlations from S penetrate into F, but this proximity effect decays over a very short distance due to the large energy splitting between the spin-up and spin-down electrons. Theory predicts that, under certain conditions, electron pair correlations will appear with spin-triplet rather than spin-singlet symmetry [1].

Continue reading… Combining superconductors and ferromagnets: a new type of symmetry? – Norman Birge

The basic tenets of the prevailing cosmological paradigm – Lambda-Cold Dark Matter – are generally well understood and robust to large scale observables, such as the cosmic microwave background and galaxy clustering. The past few years has seen the focus of cosmological studies shift into a new “precision” regime. Modern simulations of galaxy formation are very successful at using our current, incomplete, understanding of baryonic evolutionary processes to provide testable predictions about the small scale distribution of mass and light in and around galaxies. The onus, therefore, is to obtain data which will provide critical tests of the models on galactic scales and hence advance these important cosmological theories.

Continue reading… Stars, galaxies and cosmology in the nearby Universe [joint with Astronomy] – Alan McConnachie

A laser is an optical device that transforms incoherent input energy (the pump), into coherent outgoing radiation in a specific set of modes of the electromagnetic field, with distinct frequencies. There is a threshold pump energy for the first lasing mode, and above that energy the laser is a non-linear device, and non-linear interactions strongly affect the emission properties of the laser. Surprisingly, the electromagnetic theory of non-linear steady-state multimode lasing remained rather rudimentary until recently. Motivated by the complex laser cavities being developed in modern micro and nano-photonics, we have developed a new formalism, Steady-state Ab initio Laser Theory (SALT),

Continue reading… Lasers and Anti-lasers – A. Douglas Stone

Because fluids flow and readily change their shape in response to small forces, they are often used to model phenomena as diverse as the dynamics of star formation or the statics of nuclear shape. Moreover, fluids can easily break apart and thus are also an excellent starting point for investigating topological transitions. Although part of our common everyday experience, these transitions are far from understood. In this lecture, I will give the life history of a liquid drop – from its birth as a pendant fluid to its eventual demise, after splashing, as it vanishes into air. During its brief life,

Continue reading… The Life and Death of a Drop: Topological Transitions and Singularities – Sidney Nagel

The National Science Foundation Center for Layered Polymer Systems (CLiPS), in its sixth year at CWRU, is focused on a novel multilayer co-extrusion technique, which is a highly scalable roll-to-roll process capable of producing many square meters of periodic layered films in minutes. Co-extruded polymer films already have a number of applications, and research is now aimed at exploring optical and electronic phenomena and applications. Depending on the layer dimensions and periodicity, these films could act as gradient refractive index materials, photonic crystals, and other optical multilayer structures. Of particular interest is imparting to one of the layer types such functions as stimulated emission,

Continue reading… Multilayer Polymer Photonics: From “Origami” Lasers to Optical Data Storage to Cavity Polaritons – Ken Singer

Space missions have uncovered a rich, and high amplitude, pulsation spectrum in red giant stars. The information encoded in the pulsation frequencies is transforming our understanding of stars. At one level, crucial information (such as mass, radius, and age) can be used for stellar population studies. At another, we can make critical tests of stellar physics with new seismic observables (such as core rotation, convection zone depth, and core mass.) In this talk I begin by reviewing the pulsation properties of giants. I’ll then cover the likely cause of the observed frequency patterns, highlighting the role of strong coupling between core g-modes and envelope p-modes.

Continue reading… The Red Revolution: How Seismology of Red Giants is Transforming Stellar Physics and Stellar Population Studies [joint with Astronomy] – Marc Pinsonneault

Beginning around 1945, an American Abstract Expressionist painter Jackson Pollock invented and perfected a new artistic technique based on pouring and dripping liquid pigment onto a canvas stretched horizontally on the floor. In so doing, he creatively engaged fluid phenomena, in effect inviting physics to co-author his pieces. Long recognized as important and influential by art historians, Pollock’s works, and the tangled webs he created, have recently received attention also from scientists. But although the artist manipulated gravitational flows to achieve his aims, the fluid dynamical aspects of his process remained largely unexplored. I will discuss Pollockian Mechanics-the physics of lifting paint by viscous adhesion and dispensing it in free jets-focusing on the role of fluid instability.

Continue reading… Pollockian Mechanics: Painting with Viscous Jets – Andrzej Herczyński

The viscosity of strongly interacting quantum fluids has recently been examined in diverse areas of physics – black holes and string theory, quark-gluon plasmas and cold atoms – which, at first sight, appear to have little in common. In this colloquium, I will focus on the viscosity of ultracold Fermi gases, for which the most controlled experiments should be possible. I will begin with an introduction to the problem of viscosity of quantum systems and a review of the theoretical and experimental progress in exploring the BCS-BEC crossover of ultracold Fermi gases. I will then discuss connections between transport and thermodynamics across the entire crossover using exact sum rules,

Continue reading… Viscosity of Strongly Interacting Fermions – Mohit Randeria

GLENN STARKMAN (Dept. of Physics) will present on the Nobel Prize in Physics: The 2011 Nobel Prize in Physics was awarded to leaders of two collaborations that in 1998 discovered that the expansion of the universe is accelerating. We will review the evidence they presented for that claim, and briefly discuss possible explanations such as dark energy and modifications to the standard theory of gravity and General Relativity. MAN-SUN SY (Dept. of Pathology) will present on the Nobel Prize in Medicine: Prof. Man-Sun will speak on the three recipients of the Nobel prize in Medicine in 2011. He will provide a little background regarding their original contributions,

Continue reading… The 2011 Science Nobel Prizes – What were they given for? – Glenn Starkman, Arthur Heuer, and Mansun Sy

Particles with well defined shapes can be directed to assemble into complex structures by capillarity. Here we explore two themes. First, we explore the assembly of microparticles with well-defined shapes on otherwise planar interfaces to form structures with preferred orientations and with mechanical responses that depend subtly on particle shape. Progress in developing a quantitative understanding of pair interactions and mechanics of assemblies between rod-like particles is described and compared to experiment. Experiments using microparticles with a variety of particle shapes are presented to illustrate a range of possibilities including control over preferred face for assembly and the assembly of particles with complex features in registry.

Continue reading… Oriented assembly of microparticles by capillarity – Kate Stebe

The Higgs boson is an important piece of the Standard Model of particle physics that has yet to be experimentally observed. I will give a short review of high energy colliders and particle detectors and will describe the challenges of discovering a Higgs boson with these machines. I will summarize the status of Higgs boson searches at the Tevatron Collider at Fermilab and the Large Hadron Collider at CERN and portray the excitement at these labs as we move forward towards the discovery of the Higgs.

Continue reading… Higgs Boson – on the road to discovery – Sergo Jindariani

A little more than a decade after the discovery of the accelerating universe, the nature of dark energy remains one of the greatest known yet unsolved problems in cosmology and physics. Ongoing and upcoming surveys of the cosmic microwave background and large-scale structure are excellent tools to understand dark energy. Nevertheless, it is now clear that this will be difficult, and patience in understanding dark energy may be required as I will explain. I will then review some other aspects of fundamental physics that will be sharply probed by large-scale structure. In particular, I will talk about current and future constraints on cosmological inflation using measurements of primordial non-Gaussianity and statistical isotropy of density fluctuations in the universe.

Continue reading… Fundamental Physics from Large-Scale Structure – Dragan Huterer