Vanishing of Drude Weight in Interacting Fermions on $${\mathbb Z}^d$$ with Quasi-Periodic Disorder

Journal of Statistical Physics - We provide a very simple argument showing that the $$\Phi ^4_3$$ measure does have quartic exponential tails, as expected from its formal expression. This shows...     

Selective Detection of Mg2+ for Sensing Applications in Drinking Water

A new series of ligands containing the 2-(2-hydroxy-3- naphthyl)-4-methylbenzoxazole (HNBO) fluorophore showed selectivity for Mg²⁺ ions, without the interference of Ca²⁺. The most promising representative L3 resulted the best performing sensor for Mg²⁺ both in solution and embedded in an all-solid-state optode, especially towards real samples of drinkable water.     

Existence, multiplicity and concentration of bound states for a quasilinear elliptic field equation

In this paper we study existence, multiplicity and concentration of solutions for the following nonlinear field equation where the potential V is positive and W is an appropriate singular function. Here is regarded as a small parameter. Under suitable conditions on V and W we find solutions exhibiting a concentration behaviour at an absolute minimum of V as Such solutions are obtained as local minima for the associated functional; the proofs of our results rely on a careful analysis of the behaviour of minimizing sequences and use arguments inspired by the concentration-compactness principle. Received July 21, 1999; Accepted April 9, 2000 / Published online September 14, 2000     

A purely algebraic characterization of the hyperreal numbers

The hyperreal numbers of nonstandard analysis are characterized in purely algebraic terms as homomorphic images of a suitable class of rings of functions.

     

Rigorous Proof of Luttinger Liquid Behavior in the 1d Hubbard Model

We give the first rigorous (non perturbative) proof of Luttinger liquid behavior in the one dimensional Hubbard model, for small repulsive interaction and values of the density different from half filling. The analysis is based on the combination of multiscale analysis with Ward identities based on a hidden and approximate local chiral gauge invariance. No use is done of exact solutions or special integrability properties of the Hubbard model, and the results can be in fact easily generalized to include non local interactions, magnetic fields or interaction with external potentials     

Existence of 3D-Vortices in Abelian Gauge Theories

We consider the Abelian gauge theory related to the interaction between the solitary waves of the nonlinear Klein-Gordon equation and the electromagnetic field. We analyze the existence of electromagnetostatic solutions and, in particular, of vortices. Dedicated to the memory of Professor Aldo Cossu     

Numerosities of labelled sets: a new way of counting

The notions of “labelled set” and “numerosity” are introduced to generalize the counting process of finite sets. The resulting numbers, called numerosities, are then used to develop nonstandard analysis. The existence of a numerosity function is equivalent to the existence of a selective ultrafilter, hence it is independent of the axioms of ZFC.     

Effect of the α-F̃1 center interaction on the luminescence lifetime of the F center

The presence of α and F′ centers in a F coloured KCl crystal produces an increase of the lifetime of the luminescence excited with F light. One can exclude that the increase of the luminescence lifetime arises from the contribution of an F′ excited state. The increased lifetime is studied at temperatures lower than 80°K and for some α center concentrations as a function of the initial F center concentration. The results are possibly due to the perturbation of the wavefunction of the F excited state by the α centers present after the F → F′ conversion.     

Luminescence and anisotropy decays ofN-3-pyrene maleimide labeling IgG proteins and cells

The Py.M (N-3-Pyrene Maleimide) is a dye that covalently binds to reactive amino or sulfhycryl groups to give highly fluorescent protein conjugates. Measurements of luminescence lifetimes and anisotropy decays have been performed with a Phase and Modulation Fluorometer. Complexes of Py.M-antibody (IgG antimouse) and tumoral cells C6 labeled with Py.M have been investigated. The Py.M fluorescence in buffer solution and the protein and cells natural fluorescence have been checked. For Py.M-IgG and labeled cells, the fluorescence decays present interesting behaviours. The least-squares analysis of the experimental results on Py.M-IgG complex points out two lorentzian distributions centered at 74 ns and 11 ns, on the contrary, for the labeled cells, a discrete component at 100 ns and a lorentzian distribution centered at 5 ns are shown. In both systems a weak component lower than 1 ns is observed. The fluorescence decays, mainly the long lifetime one, are very sensitive to oxygen quenching, showing the high efficiency of O₂ quenching. For samples N₂ bubbled, the lifetime experimental resuits show a decrease of the oxygen accessibility from free probe in solution to Py.M-IgG complex and to labeled cells, compatible with a more compact packing of the probe binding site. The experimental results of anisotropy decays of degassed samples show for Py.M-IgG complexes a long rotation correlation time of about 200 ns at T=5°C, assigned to overall rotation of the protein, besides shorter correlation times attributable to inner protein motions. For labeled cells, the long rotation correlation time becomes of the order of 580 ns confirming a progressive increase of the stabilization of the binding site.