Universal magnetic excitations in the cuprates

I heard a nice talk by Bernhard Keimer which included a discussion of recent RIXS [Resonant Inelastic X-ray Scattering] results on the cuprates. The relevant Nature Physics article  states

As a major result, we demonstrate the existence of spin-wave-like dispersive magnetic excitations (paramagnons) deep inside the electron–hole spin-flip continuum (up to ~300 meV), for all the investigated doping levels, with spectral weights comparable to those of magnons in the undoped parent compounds.

The work is nicely put in context in a News and Views article by Matthias Vojta.