Past Events

Astro Seminar: "The Remarkable Protoplanetary Disks HL Tau: Watching the Formation of Planets"
November 2, 2016  2:00 pm  3:00 pm
David Rittenhouse Laboratory, A4
Crystal Brogan (NRAO)
Spatially resolved ALMA studies of protoplanetary disks at millimeter wavelengths are revolutionizing the study of these precursors to solar systems. In this talk I will present results from observations of the protoplanetary disk HL Tau with 3.5 AU resolution. I will also review the diverse range of modeling work that has emerged to explain the remarkable dust ring structure of HL Tau. Finally, I will show tantalizing new observational results that suggest such structures may be ubiquitous.

Experimental Particle Physics: "DiHiggs at the LHC: Current Status and Future Prospects"
November 1, 2016  1:30 pm
David Rittenhouse Laboratory, 4C8
John Alison (University of Chicago)
I will discuss motivations for searching for diHiggs production at the LHC. Recent results and projected sensitivities will be presented with particular emphasis on the dominant hh>4b channel.

MathBio seminar: "Vector diffusion maps and the graph connection Laplacian"
October 31, 2016  4:00 pm  5:00 pm
Carolyn Lynch Laboratory, 318
Amit Singer, Princeton University
Vector diffusion maps (VDM) is a mathematical framework for organizing and analyzing highdimensional datasets that generalizes diffusion maps and other nonlinear dimensionality reduction methods, such as LLE, ISOMAP, and Laplacian eigenmaps. Whereas weighted undirected graphs are commonly used to describe networks and relationships between data objects, in VDM each edge is endowed with an orthogonal transformation encoding the relationship between the data at its vertices. The graph structure and orthogonal transformations are summarized by the graph connection Laplacian.

High Energy Theory: Relative Entropy of Excited States in Conformal Field Theories
October 31, 2016  11:14 am
David RittenhouseLaboratory, 2N36
Gabor Sarosi (VUB)
We study the relative entropy between the reduced density matrices obtained from globally excited states in conformal field theories of arbitrary dimensions. We find a general formula in the small subsystem size limit. When one of the states is the vacuum of the CFT, our result matches with the holographic entanglement entropy computations in the corresponding bulk geometries, including AdS black branes. We also discuss the first asymmetric part of the relative entropy and comment on some implications of the results on the distinguishability of black hole microstates in AdS/CFT.

Topology Workshop
October 29, 2016  9:30 am  6:00 pm
David Rittenhouse Laboratory, A4
Professors Randall Kamien, Robert MacPherson, and Konstantin Mischaikow
For more information or to register, please go here: https://goo.gl/5TKikP

Experimental Particle Physics: "Improving T2K Oscillation Results with a Maximum Likelihood Event Reconstruction"
October 27, 2016  3:00 pm
David Rittenhouse Laboratory, A6
Andrew Missert (University of Colorado, Boulder)
The TokaitoKamioka (T2K) experiment is an acceleratorbased longbaseline neutrino oscillation experiment that uses a unique offaxis neutrino beam to precisely measure the parameters that govern neutrino flavor oscillations. This talk will outline the experiment and the current results, which offer tantalizing hints regarding the existence of CP violation in the neutrino sector.

Condensed Matter seminar: "Life as an emergent phenomenon: how local interactions lead to biological function at the global scale"
October 26, 2016  4:00 pm  5:00 pm
David Rittenhouse Laboratory, A4
Timon Idema, Delft University of Technology
Life exists by virtue of collective phenomena. From the cells in a tissue down to the proteins inside a cell, cooperation is key for function and thus survival. We study the physics of these manycomponent systems, looking for the emergent behaviour that underlies many biological processes. Moreover, we do so while taking the direct environment of our objects of interest into account.

Astro Seminar: "Living la vida loca: How to Assemble a Massive Dead Galaxy by z=1.01.5"
October 26, 2016  2:00 pm  3:00 pm
David Rittenhouse Laboratory, A4
Helena DominguezSanchez (Universidad Complutense de Madrid)
Three billion years after the big bang (at redshift z = 2), half of the most massive galaxies were already old, quiescent systems with little to no residual star formation. How were the lives of these galaxies so they died so fast? In this talk, I present recent results on the Star Formation Histories (SFHs) of a sample of ~ 100 quiescent massive (log M > 10 M☉) galaxies at z=1.0  1.5.

MathBio seminar: "Quantitative methods for comparing T cell repertoires"
October 24, 2016  4:00 pm  5:00 pm
Carolyn Lynch Laboratory, 318
Philip Johnson, Univesity of Maryland
The vertebrate T cell adaptive immune response has the challenging task of recognizing all possible pathogens while not attacking "self." Evolution's solution to this challenge has been to generate a repertoire of T cells within a single individual via a process of recombination and intraindividual selection that creates a vast diversity of distinct T cell receptors (TCRs). The subset of this repertoire that respond to any particular infection can be qualitatively described as broad or narrow and public or private.

High Energy Seminar: "Recent Developments in 3D Dualities"
October 24, 2016  2:00 pm
David Rittenhouse Laboratory, 2N36
Jeff Murugan (University of Cape Town)
This summer has seen a flurry of activity in particlevortex duality and, more generally, in nonsupersymmetric dualities in three spacetime dimensions. Much of this work has been directly related to the properties of socalled topological quantum matter and gapped phases of matter. In this talk, I will give a moreorless pedagogical introduction to these ideas, beginning with the sineGordon/massive Thirring correspondence and building toward our current understanding of the 3dimensional web of dualities.