Integrable Impurities as Boundary Conditions

TL;DR

This paper explores the use of integrable impurities as boundary conditions in quantum transport problems, demonstrating their transparency and effect on system size, and applying them to study conductance in interacting systems.

Contribution

It introduces integrable impurities as boundary conditions in quantum transport, showing they enhance density of states and are transparent, facilitating accurate conductance measurements.

Findings

Impurities increase the density of states at the Fermi surface.

Impurities are transparent and do not affect transport measurements.

Applied to study conductance of an interacting scatterer.

Abstract

A few exactly solvable interacting quantum many-body problems with impurities were previously reported to exhibit unusual features such as non-localization and absence of backscattering. In this work we consider the use of these integrable impurities as boundary conditions in the framework of linear transport problems. We first show that such impurities enhance the density of states at the Fermi surface, thus increasing the effective system size. The study of the real time-dynamics of a wave packet sent through a series of them inserted in both non-interacting and interacting leads then indicates that these impurities are transparent and do not add artefacts to the measurement of transport properties. We finally apply these new boundary conditions to study the conductance of an interacting scatterer using the embedding method.