Events

Abstract:
Introduction: Stereotactic Radiosurgery is the delivery of a large, highly focused radiation dose to well defined targets in the brain. This thesis explores linac-based inverse planning algorithms that can be implemented to improve the dosimetric and delivery performance of Volumetric ModulatedArc Therapy treatments for these indications.

Our group is investigating the mechanics of a key structural protein, collagen, which is comprised of three chains that coil to make a triple helix. Collagen is the fundamental structural protein in vertebrates and is widely used as biomaterial, for example as a substrate for tissue engineering. In spite of its prevalence and mechanical importance in biology, the mechanics of collagen is surprisingly unresolved.

Our group is investigating the mechanics of a key structural protein, collagen, which is comprised of three chains that coil to make a triple helix. Collagen is the fundamental structural protein in vertebrates and is widely used as biomaterial, for example as a substrate for tissue engineering. In spite of its prevalence and mechanical importance in biology, the mechanics of collagen is surprisingly unresolved.

I will first give a review of the thermodynamics of the anyon model and the Lowest Landau Level (LLL) anyon model (i.e. anyons coupled to a strong  external magnetic field), in  relation to that of the Calogero model and Haldane fractional statistics. Then  I will construct  explicitly an $N$-body kernel which  maps Calogero eigenstates onto anyonic eigenstates (arXiv: 1805.09899).

Symmetry principles are basic tenets for our theory of fundamental interactions. While they have been essential in building the theory, it is in their violations were major breakthroughs have often occurred. We will discuss how searches for symmetry violations can play a key role in elucidating the details of the fundamental forces.  We will focus on the role of past and future precision measurements using free neutrons.

With the advent of the Gaia mission, astrometry is experiencing a renaissance. Although Gaia will make important breakthroughs in many different areas, stars in the crowded central fields of globular clusters and at the faint end of the color-magnitude diagram are out of Gaia's reach. However, the stable environment of space makes the Hubble Space Telescope (HST) an excellent astrometric tool.  Its diffraction-limited resolution allows it to distinguish and measure positions and brightnesses for faint stars all the way to the center of most globular clusters.

The Cosmic Gravitational Wave Background (CGB) is a
hypothesized relic radiation field that, if detected, would give us
clues to the earliest moments of the history of the Universe. In this
talk, accessible to students and non-experts, I will describe the
physical processes that can give rise to a CGB, novel features including
a net polarization of the gravitational waves (as distinct from the
polarization of cosmic microwave background photons), and methods of
detection. I will also discuss the ability of the proposed Laser

Over the past decade, Resonant Inelastic X-Ray Scattering spectroscopy (RIXS) has been established as a powerful technique to study the energy-momentum structure of charge, orbital, lattice, and magnetic excitations of strongly correlated materials.
The computation of RIXS spectra starting from model Hamiltonians is often a formidable task because of the absence of accurate many-body tools,
particularly when many orbitals are active. In most cases, exact diagonalization (ED) techniques are used which restricts clusters to a relatively small size.

Profound developments in our understanding of the Earth, Moon, and other planetary bodies have been enabled by rotation studies.  I will describe the application of a new Earth-based radar technique that enables high-precision measurements of planetary spin states and provides powerful probes of planetary interior structure and processes.

Dr. Francois Bouchet will describe current observations that precisely constrain the nature of the Cosmos in which we live, leading to radical ideas for the origin of the structures within it. These touch on  questions such as: How did the Universe originate? What is it made of? Why is it the way that it is? What is the nature of the Dark Matter and Dark Energy that dominate the Universe?  How do we actually learn about these? And what are the new mysteries that our observations are revealing?

(No prior knowledge of biology is required for this talk!) For decades, scientists have argued about how living cell membranes acquire and maintain regions enriched in particular lipid and protein types. One of the more contentious theories has been that lipids and proteins spontaneously phase separate within the plane of the membrane to create liquid regions that differ in their composition. Physicists have long observed this type of demixing in simple artificial membranes. Clear identification of the same transition in a living biological system has heretofore been elusive.

Abstract:
We study the noncommutative geometry associated to matrices of N quantum dots in the matrix models. The earlier work established a surface embedded in flat R^3 from three Hermitian matrices. We construct coherent states corresponding to points in the emergent geometry and find the original matrices determine not only shape of the emergent surface, but also a unique Poisson structure. We prove that commutators of matrix operators correspond to Poisson brackets. Through our construction, we can realize arbitrary noncommutative membranes embedded in R^3.

Inclusion of topological phenomena in condensed matter physics over the past 10 years ushered a revolution in this field. As a result of the new theoretical insights entire classes of materials with exotic properties have been discovered, including topological insulators, Dirac and Weyl semimetals as well as topological superconductors containing Majorana fermions. In this talk I will give a brief review of these developments and discuss an intriguing connection noticed recently by Kitaev between one such topological system – the Sachdev-Ye-Kitaev model – and the horizon of a black hole.

Please join us before the Colloquium in Hennings 318 for coffee, tea and snacks at 2:45 pm

Electromagnetic probes represent a fundamental tool to study nuclear structure and dynamics. The perturbative nature of the electromagnetic interaction allows for a clean connection between calculated nuclear structure properties and measured cross sections. Ab initio methods

Quantized comological spacetimes and higher spin gauge theory in the IKKT model