Past Events

  • Condensed Matter Seminar: "Soft complexity in gels: network connectivity, viscoelasticity and failure"

    David Rittenhouse Laboratory, A6

    Emanuela Del Gado, Georgetown University

    Soft matter (colloids, polymers, proteins…) often self-assembles into gels with diverse structure and mechanics, ubiquitous in nature and extensively used to improve diverse industrial products, where they provide texture, softness, and stability. Through the interplay between their microstructure with an imposed deformation, they can be stretched, flow, squeezed or fractured, but controlling and being able to design such processes (think for example to soft inks for 3D printing technologies) requires a fundamental understanding that is still lacking.

  • Condensed Matter Seminar: "Terahertz-frequency light fields driving quantum material electrons, ions, and spins"

    David Rittenhouse Laboratory, A6

    Keith Nelson, Massachusetts Institute of Technology

    Terahertz-frequency light pulses can now be generated routinely with field amplitudes sufficient to drive highly nonlinear responses of materials and molecules.

  • Condensed Matter Seminar: "Adhering, wrapping, and bursting of fluid membranes: understanding effects of membrane-binding particles and polymers"

    David Rittenhouse Laboratory, A6

    Anthony (Tony) Dinsmore, University of Massachusetts, Amherst

    Proteins and membranes form remarkably complex structures that are key to intracellular compartmentalization, cargo transport, and cell morphology. Despite this wealth of examples in living systems, we still lack design principles for controlling membrane morphology in synthetic systems. With experiments and simulations, we show that even the simple case of spherical nanoparticles binding to lipid-bilayer membrane vesicles results in a remarkably rich set of morphologies that can be reliably controlled via the particle binding energy.

  • 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?

  • 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.

  • TODAY'S SEMINAR IS CANCELED 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

    TODAY'S SEMINAR IS CANCELED

  • 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.

  • Condensed Matter Seminar: "Soft Matter Physics of the Evolution of Multi-Cellularity"

    David Rittenhouse Laboratory, A6

    Peter Yunker, Georgia Institute of Technology

    The evolution of multicellularity set the stage for an incredible increase in the diversity and complexity of life on Earth. The increase in biological complexity associated with multi-cellularity required parallel innovation in the mechanical properties of multi-cellular bodies. Though a cursory review of any multi-cellular organism provides an appreciation of this intertwining of biological and mechanical complexity, little is known about how such mechanical properties may have evolved.

  • Condensed Matter Seminar: "Physics and Applications of Mesoscopic Optics"

    David Rittenhouse Laboratory, A6

    Hui Cao, Yale University

    Random scattering of light, e.g., in paint, clouds, and biological tissue, is a common process of both fundamental interest and practical relevance. The interference of multiply scattered waves also leads to remarkable phenomena in mesoscopic physics such as Anderson localization and universal conductance fluctuations. In applications, optical scattering is the main obstacle to imaging or sending information through turbid media.

  • Condensed Matter Seminar: "The physical chemistry of natural selection: How can we explain the high yields and high rates of biochemical reactions?"

    David Rittenhouse Laboratory, A4

    Jean-Louis Sikorav (Ministère de l'Economie et des Finances)

    The goal of this seminar is to present the main findings of an ongoing inquiry of the foundations of biology (1). The purpose of this investigation is to describe the elements, the logic and the principles of biology, and to construct biological theories using the language and the methods employed in other disciplines. This work brings to the fore the existence of a unity of knowledge, also revealed through the study of the science of research shared by all disciplines (2).