Math Physics Seminar, Simone Warzel, TU, Munich, "Decay of correlations and absence of superfluidity in the disordered Tonks-Girardeau gas"
Feb 16, 2016 · 4:30 p.m.– 5:30 p.m. · Jadwin 343
Understanding the various aspects, and even the qualitative structure of phase diagrams of interacting many-body systems in the presence of static disorder still poses a big challenge. In this context, and in view of the woefully short list of rigorous results on disordered systems with interaction, limiting or integrable model systems present a testing ground for numerical works, conjectures and ideas. The Tonks-Girardeau gas subject to a random external potential is such an example. In this talk I will give an overview of results obtained recently for this model.
(Based on joint works with R. Sims and R. Seiringer).
Feb 17, 2016 · 1:30 p.m.– 2:30 p.m. · Bloomberg Hall of Physics Library - Institute for Advanced Study
Hamilton Colloquium Series - Ryan Patterson, Caltech: "Next questions in neutrino physics and the NOvA experiment"
Feb 18, 2016 · 4:30 p.m.– 6:00 p.m. · Jadwin A10
Non-zero neutrino mass brings with it new complexity in the neutrino sector, and major questions surrounding neutrino masses and mixing remain unanswered. Among the unknowns are the ordering of the neutrino masses, key details of flavor mixing, and whether neutrinos respect CP symmetry. NOvA, a long-baseline neutrino oscillation experiment sited along Fermilab’s NuMI neutrino beam, will address these questions and much more. NOvA recently began full operations with its 14-kton detector and will continue through this decade. After a review of the physics context, I will discuss NOvA’s experimental design, physics program, and first neutrino oscillation results.
Feb 19, 2016 · 12:00 p.m.– 1:00 p.m. · PCTS Seminar Room
Feb 19, 2016 · 1:45 p.m.– 3:00 p.m. · Bloomberg Lecture Hall - Institute for Advanced Study
Biophysics Seminar - Jason Swedlow, University of Dundee "Signalling and mechanics in the human mitotic spindle and the DNA damage response."
Feb 22, 2016 · 12:00 p.m.– 1:00 p.m. · Joseph Henry Room
A hallmark of mitosis in mammalian cells is the alignment of chromosomes into a thin metaphase plate. This conserved, reproducible structure probably arises from a coordinated interaction between dynamic microtubule ends, kinetochores, molecular motors, centromeric chromatin, and the spindle checkpoint machinery, but the contributions of these different components has been difficult to discern. Our lab is interested in understanding how this structure forms, and how the individual molecules and structures contribute to the formation of the metaphase plate.
We have used a variety of tools to examine this question—proteomic analysis of chromatin at defined cell cycle states, analysis of post-translational modifications, high spatial and temporal resolution fluorescence imaging in fixed and living cells, and the development of software tools to visualize, manage, and analyse the complex datasets that this work generates.
I will describe our latest results that reveal new regulatory mechanisms that control the assembly and dynamics of mitotic spindles and microtubule-kinetochore attachments. I will focus on the function and roles of Bod1, a PP2A-B56 inhibitor, that controls the function of mitotic centrosomes and kinetochores, and its relative Bod1L that interacts with PP2A-B56 and modulates the DNA damage response.
I will also briefly mention our efforts to develop standardized interfaces for biological imaging. This project, the Open Microscopy Environment (http://openmicroscopy.org), is an open source, community-led development effort that delivers data models, file specifications, and data management software for biological microscopy.
Condensed Matter Seminar, Steve Kivelson, Stanford, "Electron Nematic Phases in Highly Correlated Electron Systems"
Feb 22, 2016 · 1:15 p.m.– 2:30 p.m. · PCTS Seminar Room
Phases of the strongly interacting electron fluid which spontaneously break the point-group symmetries of the host crystal can sometimes be characterized as “electron nematic phases.” Such phases increasingly appear to play a significant role in the physics of a variety of “interesting” materials, including the Cu and Fe based high temperature superconductors. I will review some of the evidence that this is a useful perspective (as opposed to dismissing the phenomena as an uninteresting reflection of subtle structural changes in the crystal), and will also summarize some of the theoretical progress in understanding the origins of electronic nematicity, the quantum critical phenomena associated with the transition to the nematic state, and the effect of nematic order and fluctuations on other properties of the electron fluid.
High Energy Theory - Wilke van der Schee, MIT - "Evolution of the jet opening angle distribution in holographic plasma"
Feb 22, 2016 · 2:30 p.m.– 3:30 p.m. · PCTS Seminar Room
Jets are particularly interesting probes to study the formation and evolution of quark-gluon plasma, as created in heavy ion collisions. In this talk I will briefly review attempts to describe the jet evolution in holography, and will argue that essential progress can be made by studying also the substructure of the jet, in particular the evolution of the opening angle. This is illustrated in a simple holographic model, where we start with energy and angular distributions from pQCD. We identify two competing effects: (1) all individual jets become wider, and (2) the distribution of final jets becomes narrower, since narrow jets suffer less energy loss and are thereby more likely to survive. Both effects can be visible in experimental data.
Feb 23, 2016 · 4:00 p.m.– 5:30 p.m. · Jadwin 303
Math Physics Seminar, Lukas W. Schimmer, Princeton, "Asymptotics of the eigenvalues of operators for mirror curves"
Feb 23, 2016 · 4:30 p.m.– 5:30 p.m. · Jadwin 343
Using the coherent state transform I willI establish the asymptotical behaviour of the Riesz mean for functional-difference operators associated to mirror curves of special del Pezzo Calabi–Yau threefolds.
Furthermore, I will prove the Weyl law for the eigenvalue counting function of these operators, therefore implying that their inverses are trace class.
Joint work with A. Laptev and L. A. Takhtajan.
Feb 24, 2016 · 1:30 p.m.– 2:30 p.m. · Bloomberg Hall of Physics Library - Institute for Advanced Study
Feb 24, 2016 · 2:30 p.m.– 4:00 p.m. · PCTS Seminar Room
Biological systems provide an inspiration for creating a new paradigm for materials synthesis. Imagine it were possible to create an inanimate material that could both perform some function, e.g. catalyze a set of reactions, and also self replicate. Changing the parameters governing such a system would allow the possibility of evolving materials with interesting properties by carrying out “mutation-selection” cycles on the functional outcomes. Although we are quite far from realizing such a vision in the laboratory, recent experimental advances in coating colloidal scale objects with specific glues (e.g.using complementary DNA strands) have suggested a set of theoretical models in which the possibilities of realizing these ideas can be explored in a controlled way. This talk will describe our ongoing efforts to explore these ideas using theory and simulation, and also small scale experiments.
Hamilton Colloquium Series - Joseph Curtin, Joseph Curtin Studios: “Can Stradivari’s Sound Be Measured?”
Feb 25, 2016 · 4:30 p.m.– 6:00 p.m. · Jadwin A10
A longstanding goal of violin research has been to establish objectively measurable parameters for violin quality. These would presumably substantiate one of the violin-world’s most passionately held beliefs: Violins made by Stradivari and his contemporaries in 18th Century Italy sound better than any made elsewhere or since. However, a team of researchers led by Claudia Fritz and Joseph Curtin have shown that, under double-blind conditions, neither professional violinists nor experienced listeners can tell Old Italian violins from new ones at better than chance levels. Moreover, players and listeners tend to prefer the new. Violin-maker, researcher, and MacArthur Fellow Joseph Curtin will discuss recent developments in violin science, and his own interest in measuring violin sound. He will also preview the team’s upcoming paper: “Objective parameters for violin quality.”
Feb 26, 2016 · 12:00 p.m.– 1:00 p.m. · PCTS Seminar Room
Feb 26, 2016 · 1:45 p.m.– 3:00 p.m. · PCTS Seminar Room
Feb 29, 2016 · 12:00 p.m.– 1:00 p.m. · Joseph Henry Room
Our lab focuses on mechanical studies of fundamental biological processes in biology: transcription and replication. These are highly dynamic processes that are carried out by molecular motors that translocate along, and rotate around, DNA. We are interested in forces and torques generated by these motor proteins and how their mechanics regulates transcription and replication. To directly measure these processes at the single molecule level, we develop state-of-the-art (and often one-of-a-kind) instruments and novel techniques. Our recent efforts hold promise to make these precision measurements high throughput on a nanophotonic platform.
Feb 29, 2016 · 2:30 p.m.– 3:30 p.m. · Bloomberg Lecture Hall - Institute for Advanced Study
Mar 1, 2016 · 4:00 p.m.– 5:30 p.m. · Jadwin 303
Math Physics Seminar, Michael Brenner, Harvard, "A Potential mechanism for a singular solution of the Euler Equation"
Mar 1, 2016 · 4:30 p.m.– 5:30 p.m. · Jadwin 343
I will describe a potential mechanism for a singular solution of the Euler equation. The mechanism involves the interaction of vortex filaments, but occurs sufficiently quickly and at a small enough scales that could have plausibly evaded experimental and computational detection. Joint work with Sahand Hormoz and Alain Pumir.
Mar 2, 2016 · 1:30 p.m.– 2:30 p.m. · Bloomberg Hall of Physics Library - Institute for Advanced Study
Hamilton Colloquium Series - Kerstin Perez, Haverford: “In Search of Cosmic-Ray Antinuclei from Dark Matter”
Mar 3, 2016 · 4:30 p.m.– 6:00 p.m. · Jadwin A10
Cosmic-ray antiprotons have been a valuable tool for dark matter searches since the 1970s. Recent years have seen increased theoretical and experimental effort towards the first-ever detection of cosmic-ray antideuterons, in particular as an indirect signature of dark matter annihilation or decay in the Galactic halo. In contrast to other indirect detection signatures, which have been hampered by the large and uncertain background rates from conventional astrophysical processes, low-energy antideuterons provide an essentially background-free signature of dark matter, and low-energy antiprotons are a vital partner for this analysis. I will discuss the currently planned or ongoing experiments that will be sensitive to antideuteron flux levels predicted for dark matter, focusing on the balloon-borne GAPS experiment, which exploits a novel detection technique utilizing exotic atom capture and decay to provide both a sensitive antideuteron search and a precision antiproton measurement in an unprecedented low-energy range. I will finish by looking ahead to the tantalizing prospect of cosmic antihelium measurements, as a probe of both cosmic-ray and dark matter physics.
Mar 4, 2016 · 1:45 p.m.– 3:00 p.m. · Bloomberg Lecture Hall - Institute for Advanced Study
Biophysics Seminar - Nicolas Desprat, ENS "The morphogenesis of bacterial microcolonies and its role in environmental adaptation"
Mar 7, 2016 · 12:00 p.m.– 1:00 p.m. · Joseph Henry Room
To colonize surfaces, bacteria must adhere and proliferate. How those terms compete to shape the foundations of biofilm is barely understood. When bacteria grow between a coverslip and a gel pad, they form microcolonies, which develop initially in a plane before terraces establish at their centre. In this configuration, we developed methods to probe adhesion at the scale of the microcolony and at the single cell level. We evidenced that adhesion is stronger at the old pole. During surface colonization, cell elongation is able to rupture the adhesive bonds of surrounding bacteria regardless of their position in the microcolony. However, the shape of microcolonies depends on the level of adhesion and the transition from 2D expansion to 3D growth is linearly corrleated to the strength of adhesive bonds. Finally, we showed that the microcolony of P. aeruginosa adapts its morphogenesis to maximize cell-cell contacts rather than cell-environment interactions when iron becomes scarce in the environment. In this case, reducing the surface of exchange with the environment allows to limit the loss of secreted molecules required to efficiently fetch extracelllular iron at very low concentration.
Mar 7, 2016 · 2:30 p.m.– 3:30 p.m. · PCTS Seminar Room
Mar 8, 2016 · 4:00 p.m.– 5:30 p.m. · Jadwin 303
Mar 8, 2016 · 4:30 p.m.– 6:00 p.m. · TBD
Mar 9, 2016 · 1:30 p.m.– 2:30 p.m. · Bloomberg Hall of Physics Library - Institute for Advanced Study
Mar 10, 2016 · 4:30 p.m.– 6:00 p.m. · Jadwin A10
Mar 14, 2016 · 2:30 p.m.– 3:30 p.m. · Bloomberg Lecture Hall - Institute for Advanced Study
Mar 16, 2016 · 1:30 p.m.– 2:30 p.m. · Bloomberg Hall of Physics Library - Institute for Advanced Study
Mar 18, 2016 · 1:45 p.m.– 3:00 p.m. · Bloomberg Lecture Hall - Institute for Advanced Study
Mar 21, 2016 · 12:00 p.m.– 1:00 p.m. · Joseph Henry Room
Mar 21, 2016 · 2:30 p.m.– 3:30 p.m. · PCTS Seminar Room
Mar 22, 2016 · 4:00 p.m.– 5:30 p.m. · Jadwin 303
Hamilton Colloquium Series - Vladan Vuletic, MIT: "What does the Golden Ratio have to do with friction? An answer atom by atom."
Mar 24, 2016 · 4:30 p.m.– 6:00 p.m. · Jadwin A10
Friction is the basic, ubiquitous mechanical interaction between two surfaces that results in resistance to motion and energy dissipation. To test long-standing atomistic models of friction processes at the nanoscale, we have implemented a synthetic nanofriction interface using laser cooled ions subject to the periodic potential of an optical standing wave. We show that stick-slip friction can be tuned from maximal to nearly frictionless via arrangement of the ions relative to the periodic potential, and that friction at the nanoscale can substantially differ from the simple phenomenological laws observed at the macroscale. We also establish a direct link between Aubry’s structural transition for an infinite chain in an incommensurate periodic potential, and the vanishing of friction in nanocontacts.
Mar 25, 2016 · 12:00 p.m.– 1:00 p.m. · PCTS Seminar Room
Mar 25, 2016 · 1:45 p.m.– 3:00 p.m. · PCTS Seminar Room
Hamilton Colloquium Series - David Snoke, U. Pittsburgh: "Superfluids of light: Bose-Einstein condensation of polaritons in microcavities"
Mar 31, 2016 · 4:30 p.m.– 6:00 p.m. · Jadwin A10
In specially designed solid microcavities, the photon properties can be altered to have effective mass and repulsive interactions; these new states are called "polaritons". The polaritons act like atoms, and because they are bosons, they can undergo Bose-Einstein condensation. The experiments on polariton condensation have shown truly remarkable progress in recent years, with new results showing superfluidity and quantized vorticity in a ring geometry. I will review the state of the art in the field, including results from our lab in Pittsburgh which show quantized vorticity, and measurements of the phase diagram for the polariton condensation.
Apr 1, 2016 · 1:45 p.m.– 3:00 p.m. · Bloomberg Lecture Hall - Institute for Advanced Study
Apr 4, 2016 · 2:30 p.m.– 3:30 p.m. · PCTS Seminar Room
41st Annual Donald R. Hamilton Lecture: Gary Horowitz, UC-Santa Barbara, "Strange Views of Space and Time: From Einstein to String Theory"
Apr 7, 2016 · 8:00 p.m.– 9:30 p.m. · McDonnell A02
Our understanding of space and time was revolutionized a hundred years ago by Einstein’s discovery of his special and general theories of relativity. We have recently undergone another dramatic change in our understanding of these fundamental concepts due to advances in string theory. I will describe these major developments in a nontechnical manner, and explain the strange views of space and time that we are presented with today.
Apr 8, 2016 · 1:45 p.m.– 3:00 p.m. · Jadwin A06
Apr 11, 2016 · 12:00 p.m.– 1:00 p.m. · Joseph Henry Room
Apr 11, 2016 · 2:30 p.m.– 3:30 p.m. · Bloomberg Lecture Hall - Institute for Advanced Study
Apr 12, 2016 · 4:00 p.m.– 5:30 p.m. · Jadwin 303
Apr 14, 2016 · 4:30 p.m.– 6:00 p.m. · Jadwin A10
Apr 15, 2016 · 12:00 p.m.– 1:00 p.m. · PCTS Seminar Room
Apr 15, 2016 · 1:45 p.m.– 3:00 p.m. · PCTS Seminar Room
Apr 18, 2016 · 12:00 p.m.– 1:00 p.m. · Joseph Henry Room
One of the distinguishing features of many living systems is their ability to move, to self-propel, to be active. Through their motion, either voluntarily or involuntarily, living systems are able self-assemble: birds flock, fish school, bacteria swarm, etc. But such behavior is not limited to living systems. Recent advances in colloid chemistry have led to the development of synthetic, nonliving particles that are able to undergo autonomous motion by converting chemical energy into mechanical motion and work – chemical swimming. This swimming or intrinsic activity imparts new behaviors to active matter that distinguish it from equilibrium condensed matter systems. For example, active matter generates its own internal pressure (or stress), which can drive it far from equilibrium and free it from conventional thermodynamic constraints, and by so doing active matter can control and direct its own behavior and that of its surroundings. In this talk I will discuss our recent work on swimmers and on the origin of a new source for stress that is responsible for self-assembly and pattern formation in active matter.
Apr 18, 2016 · 2:30 p.m.– 3:30 p.m. · PCTS Seminar Room
Apr 19, 2016 · 4:00 p.m.– 5:30 p.m. · Jadwin 303
A viable method for inspecting the presence of Dark Matter particles in our Galaxy is the search for an annihilation signal in the cosmic radiation, and in particular in the rare antimatter fluxes as well as in gamma rays from different regions of sky. We discuss here the recent results from the interpretation of positron and antiproton data from the AMS-02 experiment, as well as from the analysis of gamma rays measured by the Fermi-LAT.
Apr 21, 2016 · 4:30 p.m.– 6:00 p.m. · Jadwin A10
Apr 22, 2016 · 12:00 p.m.– 1:00 p.m. · PCTS Seminar Room
High Energy Theory Seminar - Andrei Smilga - Subatech Research Lab - "Ultraviolet structure of 6D sypersymmetric gauge theories"
Apr 22, 2016 · 1:45 p.m.– 3:00 p.m. · PCTS Seminar Room
N=8 supergravity is not renormalizable. This means the presense of power divergences in the amplitudes.
There are also logarithmic divergences that multiply higher-dimensional counterterms. In all probability, the latter
appear starting from the 7-th or maybe from the 8-th loop. Supergravity is extremely complicated,
and it makes sense to study simpler theories that exhibit the same properties. The
N=(1,1) supersymmetric Yang-Mills (SYM) theory in six dimensions represents such a toy model.
Nontrivial counterterms and the associated logarithmic ultraviolet divergences in the amplitudes
arise there already at the 3-d loop level.
After making some general comments on the structure of nonrenormalizable supersymmetric theories,
we will revisit the issue of higher-dimensional counterterms for N=(1,1) 6D SYM
using the off-shell N=(1,0) and on-shell N=(1,1)
harmonic superspace approaches. The second approach is developed in full generality and
used to solve, for the first time, the N=(1,1) SYM constraints in terms of N=(1,0) superfields.
This provides a convenient tool to write explicit expressions for the candidate counterterms
and other N=(1,1) invariants and may be conducive to proving non-renormalization theorems
needed to explain the absence of certain logarithmic divergences in higher-loop contributions
to scattering amplitudes in N=(1,1) SYM.
Biophysics Seminar - Sandeep Robert Datta, Harvard "Linking Sensation to Action in the Olfactory System"
Apr 25, 2016 · 12:00 p.m.– 1:00 p.m. · Joseph Henry Room
The Datta lab studies how information from the outside world is detected, encoded in the brain, and transformed into meaningful behavioral outputs. We address this fundamental problem by characterizing the olfactory system, the sensory system used by most animals to interact with their environment. Here we discuss recent results relevant to understanding sensorimotor coupling in the olfactory system. We first describe a novel molecular mechanism that underlies odor perception; this mechanism defines a new mode of sensory encoding in mammals, and is likely relevant to odor perception across deuterostomal lineages, including humans. We also describe new approaches we have recently developed to understand how genes and circuits important to sensorimotor coupling in the olfactory system might impact behavior; these methods may afford insight into mechanisms that allow animals to flexibly navigate the outside world, and serve as a quantitative prism through which the function of genes and neural circuits can be understood.
Apr 25, 2016 · 2:30 p.m.– 3:30 p.m. · Bloomberg Lecture Hall - Institute for Advanced Study
Apr 29, 2016 · 12:00 p.m.– 1:00 p.m. · PCTS Seminar Room
Apr 29, 2016 · 1:45 p.m.– 3:00 p.m. · Bloomberg Lecture Hall - Institute for Advanced Study
May 2, 2016 · 2:30 p.m.– 3:30 p.m. · PCTS Seminar Room
May 3, 2016 · 2:00 p.m.– 3:00 p.m. · PCTS Seminar Room
May 3, 2016 · 4:00 p.m.– 5:30 p.m. · Jadwin 303