Regensburg 2013 – wissenschaftliches Programm

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TT: Fachverband Tiefe Temperaturen

TT 48: Correlated Electrons: Quantum-Critical Phenomena - Theory

TT 48.3: Vortrag

Mittwoch, 13. März 2013, 17:30–17:45, H19

Universal short time dynamics after a quantum quench in the vicinity of a quantum critical point — •Pia Gagel, Peter Orth, and Jörg Schmalian — Institut für Theorie der Kondensierten Materie, Karlsruher Institut für Technologie

We investigate the dynamical evolution of the order parameter after a quantum quench from the ordered state to the quantum critical point. The calculation is done for a model relevant for quantum magnets and bosons near the superfluid insulator transition. The short time dynamics after a quantum quench is, similar to quenches near classical phase transitions, characterized by a new universal exponent. We determine this exponent using a 4-d-z and 1/N expansions and by mapping the system onto boundary layer problems. Here d is the space dimension, z the dynamic scaling exponent, and N the number of components of the order parameter. Thermalization of the post quantum quench dynamics then leads to a sequence of distinct temporal regimes that are qualitatively distinct from classical quenches. Our results demonstrate that the post quench dynamics can be used to determine the universality class of a quantum critical point.