Quasi–one–dimensional spin–Peierls and spin–ladder systems are characterized by a gap in the spin–excitation spectrum, which can be modeled at low energies by that of Dirac fermions with a mass. In the presence of disorder these systems can still be described by a Dirac fermion model, but with a random mass. Some peculiar properties, like the Dyson… (More)
We discuss the properties of interacting electrons on a finite chain with open boundary conditions. We extend the Haldane Luttinger liquid description to these systems and study how the presence of the boundaries modifies various correlation functions. In view of possible experimental applications to quantum wires, we analyse how tunneling measurements can… (More)
We study the properties of the double-frequency sine–Gordon model in the vicinity of the Ising quantum phase transition displayed by this model. Using a mapping onto a generalised lattice quantum Ashkin-Teller model, we obtain critical and nearly-off-critical correlation functions of various operators. We discuss applications of the double-sine-Gordon model… (More)
We analyze the structure of the perturbation expansion of the general multi-channel Kondo model with channel anisotropic exchange couplings and in the presence of an external magnetic field, generalizing to this case the Anderson-Yuval technique. For two channels, we are able to map the Kondo model onto a generalized resonant level model. Limiting cases in… (More)
We analyze the charge transfer statistics through a quantum dot in the Kondo regime, when coupled to an arbitrary number of terminals N. Special attention is paid to current cross correlations between concurring transport channels, which show distinct Hanbury Brown-Twiss antibunching for N>2 reflecting the fermionic nature of charge carriers. While this… (More)
A qualitative discussion of recent theoretical results in the physics of 1D quantum wires is provided here. The consideration is mainly focused on observable quantities, such as conductance, persistent current, and X-Ray response functions, which are discussed in simple terms.