Past Events

  • Special Condensed Matter Seminar: "Manipulating Charge Carriers for Quantum Transport in Van der Waals Materials Nanostructures"

    David Rittenhouse Laboratory, A4

    Ke Wang, Harvard University

    Since the discovery of graphene via mechanical exfoliation, it has been shown that the electronic properties of solids can undergo dramatic change when the material thickness is reduced to the atomic limit. Recently, the quality of these 2-dimensional (2D) electronic systems has been significantly improved by hexagonal boron nitrides encapsulation, enabling the electron mean free path only limited by the size of the samples. However, mesoscopic transport studies in these systems are relatively unexplored due to the challenges in the device fabrication processes.

  • Special Condensed Matter Seminar: "A Berry Phase Switch in Circular Graphene Resonators"

    David Rittenhouse Laboratory, A4

    Fereshte Ghahari Kermani, National Institute of Standards and Technology

    Berry phase is an example of anholonomy, where the phase of a quantum state may not return to its original value after its parameters cycle around a closed path; instead the quantum system’s wave function may acquire a real, measurable phase difference, known as Berry phase. Berry phase is connected with the geometry of the quantum system having intriguing physical consequences in systems with topological singularities, such as graphene.

  • Astro Seminar: "Massive Neutrinos and Large-scale Structure: Forecasts for SKA"

    David Rittenhouse Laboratory, A4

    Francisco Villaescusa-Navarro (Simons CCA)

    In the first part of the seminar I will discuss some of the effects that massive neutrinos induce on the large-scale structure of the Universe, from their impact on the clustering of halos, galaxies and voids to their signatures on the BAO. In the second part of the seminar I will discuss the possibility of using the hydrogen 21cm line to study cosmology.

  • Math-Bio seminar: "Covariate-corrected biclustering methods for gene-expression and GWAS data"

    318 Carolyn Lynch Laboratory

    Adi Rangan, New York University

    A common goal in data-analysis is to sift through a large matrix and detect any significant submatrices (i.e., biclusters) that have a low numerical rank. To give an example from genomics, one might imagine a data-matrix involving several genetic-measurements taken across many patients. In this context a ‘bicluster’ would correspond to a subset of genetic-measurements that are correlated across a subset of the patients. While some biclusters might extend across most (or all) of the patients, it is also possible for biclusters to involve only a small subset of patients.

  • Special Condensed Matter Seminar: "Shining light on topological insulators and Weyl semimetals"

    David Rittenhouse Laboratory, A4

    Liang Wu, University of California, Berkeley

    The last decade has witnessed an explosion of research investigating the role of topology in band-structure, as exemplified by the wealth of recent works on topological insulators (TIs) and Weyl semimetals (WSMs). In this talk I hope to convince you that optical probes of solids give unique insight into these topological states of matter.

  • Special Condensed Matter Seminar: "Probing Topological Valley Physics in Bilayer Graphene"

    David Rittenhouse Laboratory, A4

    Long Ju, Cornell University

    Graphene has been a model solid state system where novel quantum phenomena emerge from the interplay between symmetry, band topology and reduced dimensionality. In particular, AB-stacked bilayer graphene has a unique bandstructure with an electrically tunable bandgap and a valley-dependent Berry phase. These features result in unusual electrical and optical properties, for which optical spectroscopy/microscopy are powerful characterization tools.

  • Astro Seminar: "Quenching and Bulge Growth Over Cosmic Time in Massive Galaxies"

    David Rittenhouse Laboratory, A4

    Marc Huertas-Company (Paris Observatory)

    The life of a galaxy is a balance between processes that trigger star formation by accelerating gas cooling and others which tend to prevent stars to form by expelling or heating gas.  Over the past years, the picture is emerging that, during most of its life, a galaxy seems to live a rather quiet life, gradually growing in stellar mass through the formation of new stars which are formed at a rate remarkably proportional to its stellar mass, This is interpreted as an indirect evidence that fuel in the form of cold gas is somehow continuously being fed into the galaxies to susta

  • Math-Bio seminar: "Fast, scalable prediction of deleterious noncoding variants from genomic data"

    318 Carolyn Lynch Laboratory

    Adam Siepel, Cold Spring Harbor Laboratory

    Across many species, a large fraction of genetic variants that influence phenotypes of interest is located outside of protein-coding genes, yet existing methods for identifying such variants have poor predictive power. Here, we introduce a new computational method, called LINSIGHT, that substantially improves the prediction of noncoding nucleotide sites at which mutations are likely to have deleterious fitness consequences, and which therefore are likely to be phenotypically important.

  • Special Condensed Matter Seminar: "Non-equilibrium dynamics of a frustrated Mott insulator"

    David Rittenhouse Laboratory, A4

    Zhanybek Alpichshev, M.I.T.

    What happens to electrons when both the spin orbit coupling and inter-particle Coulomb repulsion are very strong? While SOC alone can change the topology of the single particle insulating state, even short range on-site repulsion by itself can give rise to a Mott insulator - one of the most mysterious and thought provoking phases in solid state physics. In this seminar I will talk about the behaviour of quasiparticles in a frustrated Mott insulator in the presence of strong spin-orbit coupling.
  • ADVANCES IN BIOMEDICAL OPTICS: Exploring Brain Interactions with Diffuse Optics

    B1 Stellar Chance Laboratories, 440 Curie Blvd

    Rickson Mesquita (University of Campinas)

    The human brain can be seen as a complex system due to its functional capabilities and structural organization. Indeed, previous works employing functional magnetic resonance imaging (fMRI) and electroencephalography (EEG) have shown several complex features of the brain.  In this talk I will approach how one can employ diffuse optics to reveal the brain's complex features during the resting state. In particular, I will discuss our recent results on the use of graph theory to characterize the spatial interactions of the healthy and the diseased brain. Last, I will explore potential clinical applications of our methodology, mostly on brain development and rehabilitation

    (Pizza will be served at 11:45 am)