Fall 2014 Seminar Series

Organizer: Boris Botvinnik

Seminars are at 4pm on Tuesdays in 472 Willamette and are preceded by cookies at 3:45.

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9/30/2014 Time Flies: Excess Entropy Production in a Time-dependent Universe
Michael Kellman
University of Oregon, Chemistry and Bio-Chemistry

I will review a new entropy for a system-environment "universe," going beyond the von Neumann entanglement entropy. Then I will look at how the microcanonical entropy, defined classically on the energy shell, generalizes to time-dependent quantum states for which the time-energy uncertainty relation holds.
Boris Botvinnik
10/7/2014 The Ferromagnetic Quantum Phase Transition in Metals
Dietrich Belitz
University of Oregon, Physics Department and Institute of Theoretical Science

In pure ferromagnets that allow for the Curie temperature to be tuned (e.g., by means of hydrostatic pressure) to low temperatures, the order of the transition invariably switches from second order to first order before a quantum critical point is reached. A tricritical point separates a line of second-order transitions from a line of first-order transitions, and in a magnetic field tricritical wings of first-order transitions appear that end in a quantum critical end point. This talk will present a theory that explains this remarkably universal phase diagram in terms of fundamental properties of Fermi liquids.
10/14/2014 High-precision Functional Profiling of Microbial Communities and the Human Microbiome
Curtis Huttenhower
Harvard School of Public Health

Among many surprising insights, the genomic revolution has helped us to realize that we're never alone and, in fact, barely human. For most of our lives, we share our bodies with some ten times as many microbes as human cells; these are resident in our gut and on nearly every body surface, and they are responsible for a tremendous diversity of metabolic activity, immunomodulation, and intercellular signaling. High-throughput sequencing has only recently provided a tool that allows exploration of microbial function, microbe-microbe, and host-microbe interactions in these complex and highly diverse ecologies.

Computational methods for interpreting metagenomic sequencing typically rely on the catalog of thousands of available microbial reference genomes. I will describe a series of bioinformatic approaches for interpreting microbial community sequences using these genomic resources, specifically the PhlAn tools for Phylogenetic Analysis. These provide efficient algorithms for taxonomic profiling within communities - identifying which organisms are present - for phylogenetic reconstruction and placement of new genomes, and for functional profiling and metabolic pathway reconstruction. I will further describe an application of these tools for strain tracking in microbial communities, resulting in the ability to uniquely identify individual human hosts using metagenomic codes.
Boris Botvinnik
10/17/2014 Friday 1:30pm
Improving the reporting of Higgs coupling measurements
Kyle Cranmer
New York University & ATLAS

I will identify the formal and practical challenges of reporting of Higgs coupling measurements to the broader (theoretical) community. I’ll then outline some of the progress we’ve made in on the technical side of sharing this information and the formal side in terms of decoupling theoretical uncertainty from the reported results. [arXiv:1401.0080]
Spencer Chang
10/21/2014 Theory and Phenomenology of Dynamical Dark Matter
Brooks Thomas
Reed College

Over the years, a number of simple and elegant ideas have been advanced to explain the nature and origin of the mysterious dark matter in our universe. However, over the last decade, a variety of puzzling experimental results and tantalizing potential signals have emerged which are difficult for these simple proposals to explain without modification. These results should prompt us to consider whether there are any additional, well-motivated ways of addressing the dark-matter problem which may have been overlooked because they do not conform to the conventional picture of what a dark matter candidate should "look like."

In this talk, I present such an alternative framework for addressing the dark-matter problem — one which we call Dynamical Dark Matter (DDM). Within the DDM framework, the requirement of dark-matter stability is replaced by a balancing between decay widths and cosmological abundances across a vast ensemble of individual dark-matter components whose collective behavior transcends that normally associated with traditional dark-matter candidates. In this talk, I provide an overview of the the DDM framework and discuss examples of theoretical contexts in which DDM ensembles naturally arise. I also discuss the phenomenological implications of DDM scenarios and, in particular, how DDM ensembles can potentially be distinguished from traditional dark-matter candidates experimentally at the next generation of direct- and indirect-detection experiments and at the LHC.

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Spencer Chang
10/28/2014 Illuminating New Physics Through Neutron-Antineutron Transitions
Michael Buchoff
University of Washington

Graham Kribs
10/31/2014 Friday 1:30pm TBA
Gray Rybka
University of Washington

Spencer Chang
No Speaker

No Speaker

11/14/2014 Friday 1:30pm
Itay Yavin

Spencer Chang
No Speaker

No Speaker

No Speaker

Last modified: Fr Aug 27 17:54:31 PDT 2010
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