Probing the admittance of a quantum RC device
Christophe Mora
Laboratoire Pierre Aigrain, ENS.
Lundi 03/06/2013, 14:00-15:00
Salle Claude Itzykson, Bât. 774, Orme des Merisiers
Mesoscopic circuits witness marked non-local effects in their transport properties as a result of electron coherence. A strinking consequence is that the response of a circuit in the quantum regime, that is at low energy, does not simply reduce to the response of each of its individual elements. We discuss here a simple quantum RC geometry in which a quantum dot, connected to a lead via a single-channel quantum point contact, is AC-driven by a nearby gate. par We argue that a low energy model [1] can be built for this problem that describes its low frequency admittance even in the strong Coulomb blockade regime. Our model predicts the emergence of universal and quantized expressions for the AC resistance of the circuit [2]. In the case where the RC circuit is described by the Anderson model, we derive the existence of a giant peak [3] that develops in the AC resistance as a function of magnetic field. Finally, we consider the two-channel case, where non-Fermi liquid physics arises, and discuss the crossover to Fermi liquid behaviour [4]. \ \ {}[1] M. Filippone and C. Mora, Fermi liquid approach to the quantum RC circuit: renormalization-group analysis of the Anderson and Coulomb blockade models, Phys. Rev. B 86, 125311 (2012) \ {}[2] C. Mora and K. Le Hur, Universal Resistances of the Quantum RC circuit, Nature Phys. 6, 697 (2010). \ {}[3] M. Filippone, K. Le Hur and C. Mora, Giant charge relaxation resistance in the Anderson model, Phys. Rev. Lett. 107, 176601 (2011). \ {}[4] C. Mora and K. Le Hur, Low-Frequency Admittance as Probe of Majorana Fermions, arXiv:1212.0650
Contact : Gregoire MISGUICH


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