Speaker Series WN2021
Feb. 11th, PROF. Hui deng
Experimental Condensed Matter Physics
Title: Controlling Light-Matter Couplings for New Science & Technology
Abstract: Control and understanding of light and matter coupling are ubiquitous and of fundamental importance in modern science and technology. Recently developments in materials, photonics and condensed matter physics have opened doors to exciting new opportunities to create light-matter coupled systems unavailable before, which on one hand may provide an experimental testground of novel nonlinear, many-body and/or quantum phenomena, and on the other hand may serve as a bridge between such phenomena and better technology for the future. I will discuss a few recent and future topics under this theme, using unconventional exciton-polariton systems and two-dimensional materials.
Feb. 25th, Prof. Keith Riles
Experimental Cosmology and Astrophysics
Title: Gravitational Wave Astronomy -- Listening to the Universe
Abstract: Gravitational waves are minute disturbances of space itself, which can arise from distant and massive but compact bodies, such as black holes and neutron stars. Using them, scientists are probing some of the most exotic phenomena in the Universe. Insights from discoveries made so far, including some surprising new objects, will be presented, along with the potential for new discoveries that will make gravitational waves essential to the next century of astronomy and cosmology.
mar. 25th, Student talks
Title: A Relaxation Treatment for Cluster Samples
apr. 8th, ProF. Liliana borcea
Title: On the continuum limit of inverse spectral problems
Abstract: I will discuss a classic inverse spectral problem for a Sturm Liouville differential operator in a bounded interval, which models an oscillating string. The inverse problem is to determine the composition of the string from measurements of the displacement at one end. I will explain how one can use tools from numerical linear algebra and reduced order modeling to solve this problem. I will also comment on how the simple ideas in this talk can be used for solving more challenging inverse problems.
Apr. 22Nd, Prof. Rachel Goldman
Condensed Matter Physics and Engineering
Title: Surface Dimer Engineering of Highly Mismatched Alloys
Abstract: Highly mismatched "designer" alloys are materials that contain chemical elements with very different atomic sizes and abilities to attract nearby electrons. When a few atoms with larger or smaller atomic sizes are added to a host material, its electrical and optical properties often change dramatically. For example, the incorporation of dilute fractions of nitrogen and bismuth solute atoms into III-V semiconductors induces significant energy bandgap narrowing; thus, emerging dilute-nitride-bismuthide alloys are of significant interest for long-wavelength applications ranging from temperature-insensitive laser diodes to ultra-high efficiency multijunction photovoltaic cells. While the properties of emerging dilute-nitride-bismuthide alloys are highly sensitive to local atomic environments, the solute incorporation mechanisms are not well understood. In this talk, we present combined computational-experimental studies which enabled our pioneering epitaxy and band structure engineering of GaAs(N):Bi alloys. In addition to describing recent advances in surface reconstruction-driven control of solute incorporation[i],[ii] and atomic-ordering,[iii] we present a new “magic ratio” for lattice matching of GaAsNBi with GaAs substrates.[iv] We also present a strategy for the synthesis and tailored electronic structure of III-V bismuthides for integration with III-V based electronics.