Related papers: Coherence in the Two Kondo Impurity Problem
We investigate the dependence of the ground state of a multi-level quantum dot on the coupling to an external fermionic system and on the interactions in the dot. As the coupling to the external system increases, the rearrangement of the…
An impurity four-level Kondo model, in which an ion is tunneling among 4-stable points and interacting with surrounding conduction electrons, is investigated using both perturbative and numerical renormalization group methods. The results…
We study transport properties of a charge qubit coupling two chiral Luttinger liquids, realized by two antidots placed between the edges of an integer $\nu=1$ or fractional $\nu=1/3$ quantum Hall bar. We show that in the limit of a large…
We study the Kondo effect due to the nonmagnetic impurity, e.g., Zn, in high-T_c cuprates based on the spin-change separated state. In the optimal or overdoped case with the Kondo screening, the residual resistivity is dominated by the…
We use the framework set up recently to compute non-perturbatively inelastic scattering from quantum impurities [G. Zar\'and {\it et al.}, Phys. Rev. Lett. {\bf 93}, 107204 (2004)] to study the the energy dependence of the single particle…
The problem of a spin-1/2 magnetic impurity near an antiferromagnetic transition of the host lattice is solved. The problem is shown to transform to a multichannel problem. A variety of fixed points is discovered asymptotically near the…
We investigate the boundary effects that arise when spin-$\frac{1}{2}$ impurities interact with the edges of the antiferromagnetic spin-$\frac{1}{2}$ Heisenberg chain through spin exchange interactions. We consider both cases when the…
Weak spin-orbit coupling produces very limited current induced spin accumulation in semiconductor nanostructures. We demonstrate a possibility to increase parametrically the spin polarization using the Kondo effect. As a model object we…
We show that the scaling exponent for tunneling into a quantum wire in the "Coulomb Tonks gas" regime of impenetrable, but otherwise free, electrons is affected by impurity scattering in the wire. The exponent for tunneling into such a wire…
We investigate a symmetrical double quantum dot system serially attached to the leads. The emphasis is on the numerical analysis of finite inter-dot tunneling in the presence of inter-dot repulsive capacitive coupling. The results reveal…
We show that the infrared phases of certain line defects in 2+1d quantum field theories are determined by anomalies, including anomalies in the space of defect coupling constants, together with a symmetry-refined corollary of the…
We study the possibility to observe the two channel Kondo physics in multiple quantum dot heterostructures in the presence of magnetic field. We show that a fine tuning of the coupling parameters of the system and an external magnetic field…
We analyze the interactions between two Kondo Quantum Dots connected to a Rashba-active Quantum Wire. We find that the Kondo-doublet interaction, at an inter-dot distance of the order of the wire Fermi length, is over an order of magnitude…
We consider the non-Fermi liquid quantum critical state of the spin-S two-impurity Kondo model, and its potential realization in a quantum dot device. Using conformal field theory (CFT) and the numerical renormalization group (NRG), we show…
We discuss the effect of multichannel Kondo impurities on superconductivity. In the strong coupling regime such impurities are pairbreakers, in contrast to the ordinary Kondo effect. Measurements of $T_c$-suppression may help in identifying…
We consider a large spin \bf S in the magnetic field parallel to the uniaxial crystal field, interacting with N >> 1 nuclear spins \bf I_i via Hamiltonian \cal H = -DS_z^2 - H_zS_z+ A{\bf S}\cdot \sum_{i=1}^N {\bf I}_i with A << D, at…
Quantum spin impurities coupled to superconductors are under intense investigation for their relevance to fundamental research as well as the prospects to engineer novel quantum phases of matter. Here we develop a large-$N$ mean-field…
We present an extensive study of the two-impurity Kondo problem for spin-1 adatoms on square lattice using an exact canonical transformation to map the problem onto an effective one-dimensional system that can be numerically solved using…
Motivated by recent experiments, in which the Kondo effect has been observed for the first time in a double quantum-dot structure, we study electron transport through a system consisting of two ultrasmall, capacitively-coupled dots with…
A Kondo model for three spin-one-half impurities placed at the vertices of an equilateral triangle is studied using the numerical renormalization-group method. The impurity spins can form two frustrated doublets which, because of the…