Nanoplasmonics beyond Ohm's law
  In tiny metallic nanostructures, quantum confinement and nonlocal response change the collective plasmonic behavior with important consequences for e.g. field-enhancement and extinction cross sections. We report on our most recent developments of a real-space formulation of an equation-of-motion that goes beyond the common local-response approximation and use of Ohm's law as the central constitutive equation. The electron gas is treated within a semi-classical hydrodynamic model with the emergence of a new intrinsic length scale. We briefly review the new governing wave equations and give examples of applying the nonlocal framework to calculation of extinction cross sections and field enhancement in isolated particles, dimers, and corrugated surfaces. 
N.A. Mortensen, G. Toscano, S. Raza, N. Stenger, W. Yan, A.-P. Jauho,   S. Xiao, and M. Wubs
physics.optics cond-mat.mes-hall physics.comp-ph