Seminars

Statistical Description of Hamiltonian Mixed Phase space systems and many Body Localization Typical physical systems follow deterministic behavior. This behavior can be sensitive to initial conditions, such that it is very difficult to predict their behavior in the longtime limit. The resulting motion is chaotic and looks stochastic or random...

Detecting emotional situations using convolutional neural networks and distributed models of human brain activity Emotions are thought to be canonical responses to situations ancestrally linked to survival or the well-being of an organism. Although sensory elements do not fully determine the nature of emotional responses, they should be sufficient to...

Generalized dispersion relation predicts harmonic generation in strongly nonlinear systems In recent work, we have derived an exact nonlinear dispersion relation for elastic wave propagation in a thin rod (linearly nondispersive) and a thick rod (linearly dispersive). The derivation is generally applicable to any type of nonlinearity, geometric (related to...

Neuroendocrine stress response and PTSD The hypothalamic-pituitary-adrenal (HPA) axis is a neuroendocrine system that regulates numerous physiological processes. Disruptions are correlated with stress-related diseases such as PTSD and major depression. We characterize normal and diseased states of the HPA axis as basins of attraction of a dynamical system describing the...

A touch of non-linearity in fluid fields: where spheres “think” collectively and swim together From crawling cells to orca whales, swimming in nature occurs at different scales. The study of swimming across length scales can shed light onto the biological functions of natural swimmers or inspire the design of artificial...

Title: "Efficient representation of high-order finite element operators" Abstract: We present an extensible low-level library that provides a versatile algebraic interface and optimized implementations suitable for high-order operators: libCEED. This library aims to overcome the challenges in high-order methods that use global sparse matrices as operator representations. In fact, one...

Dynamics of Nonlinear Random Walks on Complex Networks Random walks serve as an important tool in the complex networks community due to widespread applications including Google’ PageRank algorithm, community detection, network exploration, and modeling transport. A typical random walk on a network consist of a linear discrete-time dynamical systems, or...

Stars are filled with sound. Turbulent convection within a star makes a broadband hum, but certain frequencies get amplified because they are resonant. For example, the Sun’s surface throbs and rings under the combined influence of several million resonant acoustic modes. Thus, stars act like really bad-sounding musical instruments. Helioseismology...

Private AI (or: How to Keep Your Location Data Secret) As the world rushes towards the adoption of Artificial Intelligence (AI) in all aspects of our lives, the promise is great, but the risks are many. AI can help to improve and simplify our daily lives and introduce new types...

Topologically Protected Edge Modes in Longitudinally Driven Waveguides A tight-binding approximation is developed for deep longitudinally driven photonic lattices. The physical system considered is that of a laser-etched waveguide array which is helically-varying in the direction of propagation. Focus is placed on the so-called Lieb and Kagome lattices. The lattice...