Date

Talk

Thursday
January 8

Available

Thursday
January 15

Thursday
January 22

Available

Thursday
January 29

Available

Thursday
February 5

Available

Thursday
February 12

Jeff Kenney

Yale University

"How Galaxies are Transformed by Ram Pressure Stripping"

Abstract: I describe how galaxies are transformed by ram pressure stripping, the removal of a galaxy's gas by the galaxy's motion through an external medium. Since gas is the raw material for star formation, the loss of gas transforms galaxies from actively star forming to "dead". I focus on 2 spectacular examples of stripping in action. Remarkable dust extinction features in deep Hubble Space Telescope images of a spiral galaxy in the Coma cluster show in unprecedented ways how ram pressure strips the gas from the disk of a spiral galaxy. Ultraviolet and optical images of the Virgo Cluster dwarf irregular galaxy IC3418 show an impressive tail of UV-bright knots, head-tail, and linear stellar features formed in gas stripped from the main body of the galaxy. IC3418 appears to be a "smoking gun" example of the transformation of a dwarf irregular into a dwarf elliptical by ram pressure stripping. Studies like these illustrate the importance of stripping as a star formation quenching mechanism throughout the universe.

Thursday
February 19

Kirk Wegter-McNelly

Union College

"Entanglement at Large: Evidence for Nontrivial Quantum Behavior in Macroscopic Systems."

Abstract: With the quantum and relativistic domains having garnering so much attention over the past century, it is easy to assume that the physics of everyday life—the universe's “macroscopic middle” in which we find ourselves—has few remaining surprises in store. Whereas we have learned to expect the unexpected at the atomic and galactic scales, we now think we know what to expect from the physical world at the scale of our own existence. In this talk, I first consider how physicists came to think that everyday physical processes are somehow protected against the strange behaviors of nature’s extremes, in particular those associated with the quantum realm. I then discuss recent experiments that point in a different direction, namely, toward the possibility of nontrivial manifestations of quantum behavior in the macroscopic world via the dynamics of “entanglement.”

Thursday
February 26

Founder's Day

Thursday
March 5

Bard College

"Exploring Nanoscale Material Properties through Quantum Mechanics and High-Performance Computing"

Abstract: Density functional theory (DFT) is a powerful method used to obtain solutions to the many-electron Schrӧdinger equation in condensed matter systems, and calculations using DFT are particularly well-suited for parallelization over as many as several thousand computer cores. DFT can be used to study the structural, electronic and vibrational properties of nano-structured materials from a first-principles perspective without the need for experimental parameterization. In this talk, I will discuss some DFT calculations and their application to nano-materials of technological relevance, in particular materials that could be for future nano-electronic device technology. Specific applications include mapping the free energy landscape for impurity diffusion across semiconductor interfaces, understanding the enhanced electrical conductance of ultra-small metallic nanowires, and tuning the electronic properties of carbon nanotubes through the dielectric environment. Ongoing and future work includes modulating the work functions of metallic nanowires wires and carbon nanotubes, exploring electric field effects in two-dimensional semiconductors like MoS2 and using a Non Equilibrium Green’s Function formalism to study electron transport in molecular devices. These studies suggest new ways of manipulating quantum transport in atomic scale materials.

Thursday
March 12

Mike Mastroianni '07

" Explaining patterns: an explanatory history of select gender patterns in undergraduate STEM"

Abstract: In this talk, I will offer historical accounts of three time periods in undergraduate STEM with importance to the gender gap. Specifically, I will use social, economic, and more general historical data to develop a clear and powerful explanation of baccalaureate trends in biology and engineering.  I will discuss 1) a ten-year period in undergraduate biology in which the number of baccalaureates awarded to men decreased 44 percent, while the number of baccalaureates awarded to women decreased one percent; 2) a twenty-year period in which the number of bachelor’s degrees awarded in the biological sciences grew 150 percent—from 36,068 degrees in 1989, to 90,003 bachelor's degrees in 2011; and 3) a ten year period in undergraduate engineering where female graduation rates septupled—this ten-year time period is the only instance of meaningful and noteworthy growth for women in undergraduate engineering over the past half century.  At the end of my talk, I will discuss implications for undergraduate STEM moving forward.  

Schedule for Spring 2015