Dr. Drew Chieda, ASML

Physics Ph.D.’s in Private Sector Careers


Careers outside academia are a less common choice for Ph.D. physicists. Drew Chieda (Ph.D. 2012) took the less common path and is currently employed by ASML where he provides technical oversight into the development of semiconductor lithography tools.

This talk will be an open discussion forum where Drew will share his experiences and motivations to transition into the private sector. He will review some of what ASML does and why it’s interesting work (for him), where some of his friends and former students are employed, how his Ph.D. skills fit into a commercial environment, and some interesting data from the American Institute of Physics.

Please come with questions!

Prof. Tracy Webb, Department of Physics, McGill University

The Growth of the Most Massive Galaxies in the Highest Density Regions: Evidence for In-Situ Star Formation in Brightest Cluster Galaxies


The most massive galaxies in the local universe reside at the centres of galaxy clusters. These so-called Brightest Cluster Galaxies (BCGs) exhibit, as a class, highly uniform properties and are distinct from the general galaxy population. This suggests formation processes which are themselves distinct from those which dominate in massive galaxies outside of cluster cores. The mass growth of BCGs is likely linked to the overall physics of hierarchical structure formation on galaxy cluster scales, including the fundamental processes of gas cooling, star formation, energy feedback and galaxy mergers, at the centers of giant dark matter halos. In this talk I will present new results from the largest study of high-redshift BCGs conducted to date, drawn from the SpARCS optical/NIR cluster survey. Using archival infrared data we show the star formation rate within BCGs increases to z~2, and can add as much mass to the BCG population as the previous standard model of growth by dry mergers. At low redshifts, and in X-ray/SZ selected clusters, the rare examples of star forming BCGs appear to be fed by large-scale cooling flows. However, the first of the SpARCS systems we have studied in detail, SpARCS1049, has revealed a very different phenomenon – a train-wreck of a galaxy merger at the center of the cluster. This is the first example of such a process in high-redshift cluster cores and may represent a new phase of BCG evolution, previously unaccounted for.

Coffee and tea will be served prior to the talk, at 3:00 p.m., In Room GW-103

Prof. Gerald Dunne, Department of Physics, University of Connecticut

Resurgent Extrapolation: Squeezing Non-Perturbative Information from Perturbation Theory


Extrapolation is an important problem in physics: how to use asymptotic data in one parametric regime to learn about the behavior of a physical function in another parametric regime. For example: extending weak coupling expansions to strong coupling, or high temperature expansions to low temperature, or vice versa. I present new methods from "resurgent asymptotics" that dramatically improve standard numerical procedures for performing such an extrapolation: Borel summation, Pad'e approximants and conformal mapping. I illustrate the method with the concrete example of one of the Painlev'e equations, a class of nonlinear equations with many applications in physics. Starting solely with a finite number of asymptotic coefficients, we obtain a high precision extrapolation of the function throughout the complex plane, even across a phase transition. The precision far exceeds that of state-of-the-art numerical integration methods.

Dr. Ryan Carollo,
Department of Physics and Astronomy, Bates College

Blowing Bubbles... in Space!

Bose-Einstein condensates (BECs) can be used as sensitive probes or tests of delicate physics. However, gravitational sag equivalent to 100 nanokelvin per micron can adversely affect sensitive measurements or delicate potentials. NASA and JPL have solved this problem by installing a BEC machine (the Cold Atom Laboratory - CAL) on the International Space Station. We're using it to blow bubbles - fully-connected, quasi-2-dimensional shells of weakly-trapped condensate - and study them in a shape that can't be achieved on Earth.

SPS colloquium