Events

  • Condensed Matter Seminar: "Learning force fields from stochastic trajectories"

    David Rittenhouse Laboratory, A6

    Pierre Ronceray, Princeton University

    From nanometer-scale proteins to micron-scale colloidal particles, particles in biological and soft matter systems undergo Brownian dynamics: their deterministic motion due to the forces competes with the random diffusion due to thermal noise. In the absence of forces, all trajectories look alike: the key information characterizing the system's dynamics thus lies in its force field. However, reconstructing the force field by inspecting microscopy observations of the system's trajectory is a hard problem, for two reasons.

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  • Condensed Matter Seminar: "Let it rip: In vivo biomechanics studies of Hydra regeneration from tissue spheres"

    David Rittenhouse Laboratory, A6

    Eva-Marie Shoetz Collins, Swarthmore College

    The freshwater cnidarian Hydra is famous for its regenerative capabilities. Hydra can regenerate from small tissue pieces and from cell aggregates following complete dissociation into individual cells. We have recently shown that tissue surface tensions drive cell sorting in Hydra cell aggregates (Cochet-Escartin et al., Biophys. J. 2017).

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  • Condensed Matter Seminar: "Topological Origin of Equatorial Waves"

    David Rittenhouse Laboratory, A6

    Brad Marston, Brown University

    Topology sheds new light on the emergence of unidirectional edge waves in a variety of physical systems, from condensed matter to artificial lattices. Waves observed in geophysical flows are also robust to perturbations, which suggests a role for topology. We show a topological origin for two celebrated equatorially trapped waves known as Kelvin and Yanai modes, due to the Earth’s rotation that breaks time-reversal symmetry. The non-trivial structure of the bulk Poincare ́ wave modes encoded through the first Chern number of value 2 guarantees existence for these waves.

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  • Condensed Matter Seminar: "Taming Quantum Entanglement"

    David Rittenhouse Laboratory, A6

    Matthew Fisher, University of California, Santa Barbara

    Non-local quantum entanglement - “spooky action at a distance” - is the key feature that dis- tinguishes quantum from classical systems. The entanglement-entropy provides a measure of en- tanglement and for many-body systems is intimately connected to the thermal-entropy. Out of equilibrium, in a driven system or after a quantum quench, entanglement spreads ballistically with maximal entropy attained at long times - that is, complete disorder reigns. But not (always!) with life on earth! Why?

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  • Condensed Matter Seminar: "TBA"

    David Rittenhouse Laboratory, A6

    Anthony (Tony) Dinsmore, University of Massachusetts, Amherst

  • Condensed Matter Seminar: "TBA"

    David Rittenhouse Laboratory, A6

    Keith Nelson, Massachusetts Institute of Technology

  • Condensed Matter Seminar: "TBA"

    David Rittenhouse Laboratory, A6

    Emanuela Del Gado, Georgetown University

  • Condensed Matter Seminar: "Revisiting and Repurposing the Double Helix"

    David Rittenhouse Laboratory, A6

    Taekjip Ha, Johns Hopkins University

    DNA is an iconic molecule that forms a double helical structure, providing the basis for genetic inheritance, and its physical properties have been studied for decades. In this talk, I will present evidence that sequence and methylation dependent physical properties of DNA such as flexibility and self-association may be important for biological functions [1, 2]. In addition, I will present a new application of DNA where mechanical modulations of cell behavior can be studied at the single molecule level using rupturable DNA tethers [3].

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