Events Archive

Apr
21
2014
Spin transition in second Landau level
The fractional quantum Hall effect (FQHE) states in the second Landau level have attracted growing interests and intensive theoretical and experimental investigations due to them possibly being non-Abelian states. Recently, we systematically examined the spin polarization of the FQHE states in a series of high quality, low density two dimensional electron systems. Evidence of spin transition was observed, suggesting a more complicated nature of the FQHE ground states in the second Landau level.
Apr
16
2014
The Dynamical Structure of Electroconvecting Liquid Crystals
We utilize electroconvecting liquid crystal samples as a test bed from non-equilibrium driven systems. I will discuss results from the application of a novel mathematical analysis that incorporates time-delay embedding and diffusion maps to elucidate the underlying geometry in this system. This analysis permits the discrimination of different dynamical states from empirical data and is used to demonstrate multistability in this system. In addition we investigate the effects of an abrupt transition to defect turbulence on the structure and energy flow in this system.
Apr
15
2014
Supercomputing, Virtual screening and molecular discovery: methods, applications and challenges
We present and discuss, in the context of the drug discovery pipeline, recent computational developments that enable the virtual screening of massive databases of chemicals against a large number of protein structures. We present "ensemble docking" applications of virtual screening in multiple protein structures that identify new protein ligands and explore biochemical pathways. We also discuss fundamental and challenging aspects of these very large virtual screening approaches.
Apr
15
2014
Kinking Double-Stranded DNA by Strong Bending
Apr
14
2014
Massless and Massive Electrons: Relativistic Physics in Condensed Matter Systems
Electrons in free space have a well-defined mass. Recently, a new class of materials called topological insulators were discovered, where the low energy electrons have zero mass. In fact, these electrons can be described by the same massless Dirac equation that is used to describe relativistic particles travelling close to the speed of light. In this talk I will describe our recent experimental and theoretical investigations of Topological Crystalline Insulators (TCIs) [1]. TCIs belong to the newest category of topological materials...
Apr
03
2014
The Cosmic Dawn - Physics of the First Luminous Objects
Apr
02
2014
Inquiring Minds Lecture Series: Illustrated Special Relativity Through its Paradoxes
Mar
28
2014
TCAN Seminar: The Fueling of Active Galactic Nuclei and Supermassive Black Hole Growth
Mar
27
2014
Frustration and non-equilibrium assembly in soft condensed matter: confined crystals, aging glasses, drying drops, and more
    While we would like to avoid frustration in our daily lives, frustration in condensed matter produces novel phenomena with important consequences. Materials that are geometrically frustrated cannot minimize the energy of every particle-particle interaction, even in their ground state; materials that are kinetically frustrated are trapped out of equilibrium, i.e., they cannot reach their ground state. In this talk I will review a series of experiments I have performed investigating the role of frustration in the assembly and phase behavior of colloidal systems. By tuning particle size, shape, and confinement, I systematically varied the degree of...
Mar
27
2014
What Can Galaxy Evolution Tell Us About Short Gamma-Ray Bursts?
We use recent constraints on the star formation rate---halo mass---redshift relation to model the host halo environments where short Gamma-Ray Burst (sGRB) progenitors are created.  These halo environments set minimum energy requirements for sGRB progenitors to leave the vicinity of their original galaxy.  We find that the fraction of sGRBs which are hostless is a robust probe of the underlying velocity kick distribution for sGRB progenitors, regardless of uncertainties in the sGRB time-delay distribution and observational systematics.  We use observed constraints on the hostless fraction of sGRBs to rule out several sGRB progenitor classes which cannot supply the...

Pages