Events at Physics |
Events on Tuesday, November 14th, 2017
- Chaos & Complex Systems Seminar
- Inference for high-dimensional self-exciting point processes
- Time: 12:05 pm - 1:00 pm
- Place: 4274 Chamberlin (refreshments will be served)
- Speaker: Becca Willett, UW Department of Electrical and Computer Engineering
- Abstract: In a variety of settings, our only glimpse at a network’s structure is through observations of a corresponding dynamical system. For instance, in a social network, we may observe a time series of members’ activities, such as posts on social media. In biological neural networks, firing neurons can trigger or inhibit the firing of their neighbors, so that information about the network structure is embedded within spike train observations. These processes are “self-exciting” in that the likelihood of future events depends on past events. In these and other settings, a network’s structure corresponds to the extent to which one node’s activity stimulates or inhibits activity in another node. In this talk, I will describe sparsity-regularized inference methods and theoretical guarantees that reflect the role of the network’s degree distribution and other network properties in determining the complexity of the inference problem for large-scale networks. In addition, we will see how these techniques can be used in applications ranging from criminology to predicting adverse drug reactions.
- Host: Clint Sprott
- Council Meeting
- Time: 3:30 pm
- Place: 2314 Chamberlin Hall
- Theory Seminar (High Energy/Cosmology)
- A New Dark Matter (in)Direct Search Strategy
- Time: 3:30 pm
- Place: 5280 Chamberlin Hall
- Speaker: Doo Jin Kim, CERN
- Abstract: I propose a new dark matter (DM) detection strategy for models with a non-minimal dark sector. The strategy is to seach for relativistic, inelastic scattering signatures of DM at large-volume neutrino detectors and/or conventional DM direct detection experiments via a DM interaction with target material inside the detector. The signal process is characterized by an inelastic scattering of relativistic/boosted DM, which may arise in multi-component DM scenarios, into a heavier unstable dark-sector state which subsequently decays back into DM along with visible particles. I will argue that the presence of the secondary (visible) decay signature along with an energetic target recoil is very unique, hence allow to unambiguously separate signal events from associated background ones. I will then dicuss some interesting phenomenology including detection prospects at the above-mentioned experiments, taking the dark photon scenario as a benchmark model.