Berlin 2015 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 102: Transport: Quantum Dots, Quantum Wires, Point Contacts 2 (jointly with HL)
TT 102.6: Vortrag
Donnerstag, 19. März 2015, 16:15–16:30, A 053
Competing energy scales in the renormalization group flow of quantum dot setups with periodically varying parameters — •Katharina Eissing1,2, Dante Marvin Kennes1,2, and Volker Meden1,2 — 1Institut für Theorie der Statistischen Physik, RWTH Aachen University, 52074 Aachen, Germany — 2JARA Fundamentals of Future Information Technology, 52056 Aachen, Germany
The functional renormalization group (fRG) has proven to be a versatile tool to investigate correlated, low-dimensional systems in and out of equilibrium. It was recently extended to study quantum dot setups with explicitly time dependent Hamiltonians [Phys. Rev. B 85, 085113 (2012)]. In systems in which one or more of the dot or lead parameters are varied periodically in time a periodic steady state is reached after all transients have died out. However, due to the limited simulation time the physics of this state can only be described, if we take advantage of the periodicity by combining the Floquet theorem and set up a functional RG with Green functions written in the Floquet basis. For the interacting resonant level model which in equilibrium and if driven by a time constant bias voltage is characterized by power-law scaling of observables in the relevant energy scales (e.g. temperature T or bias voltage Vb, respectively) with interaction dependent exponents this allows to investigate if and how the driving frequency Ω acts as a cutoff of the underlying renormalization group flow. The competition of this scale with the emergent low-energy scale TK (Kondo scale) is investigated. I discuss how this competition is reflected in the observables characterizing the stationary transport through the dot.