Physics Colloquia

December, 12/05/2016
Events and times subject to change

December 8, 2016 Thursday 4:00 PM  +
Meyer 122
Physics Colloquia (colloquia)


Rob Phillips
Caltech

The Other Bohr, Allostery and Biology’s Greatest Model

Only ten years after the discovery of the iconic structure of DNA, new questions were on biologist’s minds, namely, how are the macromolecules of the cell regulated so that they do what they are supposed to when and where they are needed. The initial resolution of the challenging question of biological regulation came in the form of the notion of “allostery”, an idea that its discoverer Jacques Monod himself referred to as "the second secret of life". We recently celebrated the 50th anniversary of the classic paper of Monod, Changeux and Jacob that introduced this far reaching idea. That important paper was followed shortly thereafter by a second one that revealed their musings on how simple statistical mechanical models can be used to capture how such allosteric transitions work mechanistically. In this talk, I will review the key features of the famed Monod-Wyman-Changeux (MWC) model and then describe its broad reach across many different domains of biology with special reference to the physics underlying how genes are turned on and off. One of the intriguing outcomes of this class of models is a beautiful and predictive scheme for collapsing data from entire libraries of mutants. Once we have considered some of the traditional uses of the MWC model, I will turn to more speculative recent ideas which use the MWC approach to consider the nature of kinetic proofreading.


December 15, 2016 Thursday 4:00 PM  +
Meyer 122
Physics Colloquia (colloquia)


Jenny Hoffman
Harvard University

Imaging the Surface States of a Strongly Correlated Topological Insulator

The prediction and subsequent discovery of robust spin-polarized surface states on topological band insulators has launched a new subfield of physics over the last decade. In the last few years it has been recognized that even more interesting, exotic, and potentially useful states of matter can arise when topology is combined with strong correlations. Strong correlations can lead to new topological classifications, fractionalized states, and many-body localization that preserves the topology of the insulating state against thermal destruction. The Hoffman lab has very recently achieved the first direct proof of a strongly correlated topological insulator. Using scanning tunneling microscopy to probe real and momentum space structure, our measurements on the heavy fermion material SmB6 reveal the evolution of the insulating gap arising from strong interactions. Within the narrow gap, we directly image a dispersing surface surface state that converges to a Dirac point close to the chemical potential. Our observations present the first opportunity to explore a strongly correlated topological state.


January 26, 2017 Thursday 4:00 PM  +
Meyer 122
Physics Colloquia (colloquia)


Jane Kondev

TBA



February 2, 2017 Thursday 4:00 PM  +
Meyer 122
Physics Colloquia (colloquia)


Mehran Kardar

TBA



February 16, 2017 Thursday 4:00 PM  +
Meyer 122
Physics Colloquia (colloquia)


Eric Siggia
Rockefeller University

TBA



February 23, 2017 Thursday 4:00 PM  +
Meyer 122
Physics Colloquia (colloquia)


David Huse
Princeton University

TBA



March 9, 2017 Thursday 4:00 PM  +
Meyer 122
Physics Colloquia (colloquia)


David Holland
NYU

TBA



March 23, 2017 Thursday 4:00 PM  +
Meyer 122
Physics Colloquia (colloquia)


Raman Sundrum
University of Maryland

TBA



April 27, 2017 Thursday 4:00 PM  +
Meyer 122
Physics Colloquia (colloquia)


Daniel Whiteson
University of California, Irvine

TBA



May 4, 2017 Thursday 4:00 PM  +
Meyer 122
Physics Colloquia (colloquia)


Eva Halkiadakis
Rutgers University

TBA