Talks

I discuss how exact, non-perturbative results can be obtained for both optical transport and static susceptibilities in “Hertz-Millis” theories of Fermi surfaces coupled to critical bosons. Such models possess a large emergent symmetry and anomaly structure, which we leverage to fix these quantities. In particular, I will show that in the infrared limit, the boson self energy at zero wave vector is a constant independent of frequency, and the real part of the optical conductivity is purely a delta function Drude peak with no other corrections. I will also obtain exact relations between Fermi liquid parameters as the critical point is approached from the disordered phase. 

Zoom Link:  https://pitp.zoom.us/j/93340611986?pwd=cisrZmFxcEVWZVdrT2tMRVZiVTdRQT09

Macroecology, as a relatively new field in Ecology, holds distinct methodological characteristics that lead to profound philosophical changes in the nature of evidence to support and build theories and models. One reason for this is the impracticability of controlled or manipulative experimental studies at broad spatial and temporal scales, as well as historical contingencies and the complexity of ecological dynamics at these scales. We follow here a model-based reasoning for building scientific theories and show in particular how computer simulation models, applied to different case studies in diversity gradients, can be successfully used in macroecology as mediating theory and data.