Pablo S. Cornaglia

Pseudogap opening and formation of Fermi arcs as an orbital-selective Mott transition in momentum space

(Dated: March 16, 2009) We present an approach to the normal state of cuprate superconductors which is based on a minimal cluster extension of dynamical mean-field theory. Our approach is based on an effective two-impurity model embedded in a self-consistent bath. The two degrees of freedom of this effective model can be associated to the nodal and antinodal regions of momentum space. We find a metal-insulator transition which is selective in momentum space: At low doping quasiparticles are destroyed in the antinodal region, while they remain protected in the nodal region, leading to the formation of apparent Fermi arcs. We compare our results to tunneling and angular-resolved photoemission experiments on cuprates. At very low energy, a simple description of this transition can be given using rotationally invariant slave bosons.

Valence bond dynamical mean-field theory of doped Mott insulators with nodal/antinodal differentiation

We introduce a valence bond dynamical mean-field theory of doped Mott insulators. It is based on a minimal cluster of two orbitals, each associated with a different region of momentum space and hybridized to a self-consistent bath. The low-doping regime is characterized by singlet formation and the suppression of quasiparticles in the antinodal regions, leading to the formation of Fermi arcs. This is described in terms of an orbital-selective transition in reciprocal space. The calculated tunneling and photoemission spectra are consistent with the phenomenology of the normal state of cuprates. We derive a low-energy description of these effects using a generalization of the slave-boson method.

Mott transition of fermionic mixtures with mass imbalance in optical lattices

We investigate the effect of mass imbalance in binary Fermi mixtures loaded in optical lattices. Using dynamical mean-field theory, we study the transition from a fluid to a Mott insulator driven by the repulsive interactions. For almost every value of the parameters we find that the light species with smaller bare mass is more affected by correlations than the heavy one, so that their effective masses become closer than their bare masses before a Mott transition occurs. The strength of the critical repulsion decreases monotonically as the mass imbalance grows so that the minimum is realized when one of the species is localized. The evolution of the spectral functions testifies that a continuous loss of coherence and a destruction of the Fermi liquid occur as the imbalance grows. The two species display distinct properties and experimentally-observable deviations from the behavior of a balanced Fermi mixture.

Theory of core-level photoemission and the x-ray edge singularity across the Mott transition

The zero-temperature core-level photoemission spectrum of a Hubbard system is studied across the metal to Mott insulator transition using dynamical mean-field theory and Wilsons numerical renormalization group [Rev. Mod. Phys. 47, 773 (1975)]. An asymmetric power-law divergence is obtained in the metallic phase with an exponent

Electron-phonon correlation effects in molecular transistors

\ensuremath{\alpha}(U,Q)\ensuremath{-}1

Kondo effect with noncollinear polarized leads : A numerical renormalization group analysis

, which depends on the strength of both the Hubbard interaction

Transport through side-coupled double quantum dots: from weak to strong interdot coupling

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Spin filtering and thermopower in star-coupled quantum dot devices

and the core-hole potential

Transport through side-coupled multilevel double quantum dots in the Kondo regime

Q

Thermometry and signatures of strong correlations from Raman spectroscopy of fermionic atoms in optical lattices

. For