Dissipative dynamics of an extended magnetic nanostructure: spin necklace in a metallic environment

Mapping of the anisotropic two-channel Anderson model onto a Fermi-Majorana biresonant level model

We establish the correspondence between an extended version of the two-channel Anderson model and a particular type of biresonant level model. For certain values of the parameters the new model becomes quadratic. We calculate in closed form the entropy and impurity occupation as functions of temperature and identify the different physical energy scales of the problem. We show how, as the temperature goes to zero, the model approaches a universal line of fixed points non-Fermi liquid in nature.

Exotic Kondo effect from magnetic trimers

Motivated by the recent experiments of Jamneala et al. [Phys. Rev. Lett. 87, 256804 (2001)] by combining ab initio and renormalization group methods, we study the strongly correlated state of a Cr trimer deposited on gold. Internal orbital fluctuations of the trimer lead to a huge increase of T(K) compared to the single ion Kondo temperature explaining the experimental observation of a zero-bias anomaly for the trimers. The strongly correlated state seems to belong to a new yet hardly explored class of non-Fermi-liquid fixed points.

Prediction of the capacitance line shape in two-channel quantum dots

We propose a setup to realize two-channel Kondo physics using quantum dots. We discuss how the charge fluctuations on a small dot can be accessed by using a system of two single-electron transistors arranged in parallel. We derive a microscopic Hamiltonian description of the setup that allows us to make the connection with the two-channel Anderson model (of extended use in the context of heavy-fermion systems) and in turn make detailed predictions for the differential capacitance of the dot. Its line shape, which we determined precisely, shows a robust behavior that should be experimentally verifiable.