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  • Mar
    5

    Appl Math: Xiangyi Meng on "The shape of physical networks"

    McCormick-Engineering Sciences and Applied Mathematics (ESAM)

    11:15 AM M416, Technological Institute

    EVENT DETAILS

    Title: The shape of physical networks

    Speaker: Xiangyi Meng

    Abstract:

    The brain’s connectome and the vascular system are examples of physical networks—tangible, web-like objects that exist in real space (not just in our papers). This physical reality means these networks combine a graph structure, describing their topological connectivity, with a physical structure, capturing the shape of all nodes and links. How do we best describe this physical structure? Naturally, we model it as a geometric object, i.e., a manifold embedded in 3D space. To do this, we turn to an unexpected mathematical tool: the framework of covariant closed string field theory, developed in the 1980s. This framework provides an exact correspondence between network-like graphs and smooth surfaces. We show that, as interpreted by this string-theoretical framework, geometric objects acquire network shapes precisely because they tend to minimize their surface areas. We developed both a Riemann surface formulation and a numerical algorithm to simulate this minimization process, finding that it predicts structural features challenging traditional explanations of network formation. Specifically, this minimization predicts the emergence of trifurcations and branching angles that, while defying conventional models such as Steiner graphs, are in excellent agreement with the local tree-like organization of physical networks across diverse domains, from human neurons to corals. We conclude by discussing potential applications of this fundamental discovery, from interpreting structural changes in neurological disorders to designing novel metamaterials.

    (A popular summary of the work can be found at: Finally A Use for String Theory! https://www.youtube.com/watch?v=Hj5b0ieVWSo )

    Zoom: https://northwestern.zoom.us/j/94402153768

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    TIME Thursday, March 5, 2026 at 11:15 AM - 12:15 PM

    LOCATION M416, Technological Institute    map it

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    CONTACT Noor Kaur    noor.kaur@northwestern.edu EMAIL

    CALENDAR McCormick-Engineering Sciences and Applied Mathematics (ESAM)

  • Mar
    12

    Appl Math: Xiao Yu Wang on "What the Proposed Credit Card Regulation Really Means for Consumers"

    McCormick-Engineering Sciences and Applied Mathematics (ESAM)

    11:15 AM M416, Technological Institute

    EVENT DETAILS

    TIME Thursday, March 12, 2026 at 11:15 AM - 12:15 PM

    LOCATION M416, Technological Institute    map it

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    CONTACT Anne Umbanhowar    anne.umbanhowar@northwestern.edu EMAIL

    CALENDAR McCormick-Engineering Sciences and Applied Mathematics (ESAM)

  • Apr
    2

    Appl Math: Oleg Kirillov on "Title TBA"

    McCormick-Engineering Sciences and Applied Mathematics (ESAM)

    11:15 AM M416, Technological Institute

    EVENT DETAILS

    TIME Thursday, April 2, 2026 at 11:15 AM - 12:15 PM

    LOCATION M416, Technological Institute    map it

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    CONTACT Anne Umbanhowar    anne.umbanhowar@northwestern.edu EMAIL

    CALENDAR McCormick-Engineering Sciences and Applied Mathematics (ESAM)

  • May
    13

    Appl Math: Melanie Mitchell on "Title TBA" - Reiss Lecture

    McCormick-Engineering Sciences and Applied Mathematics (ESAM)

    11:15 AM

    EVENT DETAILS

    TIME Wednesday, May 13, 2026 at 11:15 AM - 12:15 PM

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    CONTACT Anne Umbanhowar    anne.umbanhowar@northwestern.edu EMAIL

    CALENDAR McCormick-Engineering Sciences and Applied Mathematics (ESAM)

  • May
    14

    Appl Math: Melanie Mitchell on "Title TBA" - Reiss Lecture

    McCormick-Engineering Sciences and Applied Mathematics (ESAM)

    11:15 AM

    EVENT DETAILS

    TIME Thursday, May 14, 2026 at 11:15 AM - 12:15 PM

    ADD TO CALENDAR

    CONTACT Anne Umbanhowar    anne.umbanhowar@northwestern.edu EMAIL

    CALENDAR McCormick-Engineering Sciences and Applied Mathematics (ESAM)