Exploring extreme nonequilibrium phenomena with trapped atoms

Trapped ultracold atoms enable direct experimental investigation of nonequilibrium many-body quantum dynamics, including phenomena which are difficult or impossible to investigate in the solid state. We report on progress in two such experiments using ultracold strontium: exploring the excitation structure of phasonic modes in quasicrystals and simulating attosecond-scale electron dynamics. Because phason modes involve long-range rearrangement of atoms, they are typically not dynamical degrees of freedom in solid-state quasicrystals. Uniquely, the cold atom context enables spectroscopic probes of electron-phason coupling. Separately, we discuss quantum emulation of ultrafast physics, which is enabled by equilibration timescales more than ten orders of magnitude slower than those in solids.