Form-factors computation of Friedel oscillations in Luttinger liquids

We show how to analytically determine for $g\leq 1/2$ the "Friedel oscillations" of charge density by a single impurity in a 1D Luttinger liquid of spinless electrons.Comment: Revtex, epsf, 4pgs, 2fig

Boundary interactions changing operators and dynamical correlations in quantum impurity problems

Recent developments have made possible the computation of equilibrium dynamical correlators in quantum impurity problems. In many situations however, one is rather interested in correlators subject to a non equilibrium initial preparation; this is the case for instance for the occupation probability $P(t)$ in the double well problem of dissipative quantum mechanics (DQM). We show in this paper how to handle this situation in the framework of integrable quantum field theories by introducing ``boundary interactions changing operators''. We determine the properties of these operators by using an axiomatic approach similar in spirit to what is done for form-factors. This allows us to obtain new exact results for $P(t)$; for instance, we find that that at large times (or small $g$), the leading behaviour for g < 1/2} is $P(t)\propto e^{-\Gamma t}\cos\Omega t$, with the universal ratio. $\Omega/\Gamma = \cot {\pi g}/{2(1-g)}$.Comment: 4 pages, revte

Phylogenetics of Hopbushes and Pepperflowers (Dodonaea, Diplopeltis – Sapindaceae) based on nuclear ribosomal ITS and partial ETS sequences incorporating secondary structure models

Hopbushes and pepperflowers (Dodonaea, Diplopeltis – Sapindaceae) are important components of Australia’s arid zone and sclerophyll and temperate forests and woodlands. Phylogenetic analyses of nuclear ribosomal ITS and partial ETS sequences for near-complete sampling of both genera were performed using a Bayesian statistical method and RNA specific models of nucleotide evolution that incorporate secondary structure (separate models for stems and loops). Diplopeltis is paraphyletic. Diplopeltis stuartii is not closer to other species of the genus than it is to species outside the genus. There are also several evolutionary elements in the molecular data that support D. stuartii as distinct from the other members of the genus. The monophyly of Dodonaea as redefined here to include all species of Distichostemon is unequivocally supported by the molecular data and the morphological synapomorphies of petal-less flowers with a highly reduced intrastaminal disk that is absent in staminate flowers. There do not appear to be any obvious evolutionary trends in the morphological characters (leaf and capsule form, presence or absence of aril, or breeding system) that have been previously used to group taxa. However, there are some morphological characters that may be useful to delineate some of the clades recovered in the present molecular study. New combinations in Dodonaea are made for all species of Distichostemon