University of Sherbrooke

Title:Kondo Physics with Quantum dots: How to "entangle" Spin and Charge qubits

Abstract: The presence of magnetic impurities in metals is well-known to give rise to unconventinal transport and specific heat. Already in 1963, J. Kondo taking into account the magnetic coupling between impurities and the conduction band managed to explain the anomalous behavior in the resistivity of certain metals at low temperatures. The aim of this seminar is to show at a very pedagogical level that the recent development of nanotechnology ( e.g. "quantum dots") allows to reconsider the Kondo problem at a more mesoscopic scale and at the same time to answer fundamental questions like: "What is the transport through a small quantum dot with an odd number of electrons at low temperatures?" or "What is the total capacitance of a metallic dot coupled to a bulk lead and a capacitvely connected to a back-gate?" Furthermore we emphasize the possibility to observe simultaneous orbital and spin Kondo effects and to probe the underlying spin-charge mixing (entanglement) via standard capacitive or conductance measurements; This could lead to the striking observation of new Kondo liquids with large SU(4) symmetry*.

Useful references for that point:
K. Le Hur and P. Simon, PRB 67, 201308R (2003)
K. Le Hur, P. Simon and L. Borda, cond-mat/0306186