Some curiosites about the Engel method to estimate equivalence scales

This paper lends legitimacy to the food share as an indicator of welfare by demonstrating the conditions necessary in empirical work for the Engel method of estimating equivalence scales to provide an exact measure of welfare. In analogy to a money metric of utility, the Engel's food share is shown to be a “quantity metric of utility.”Engel method

On the Compton clock and the undulatory nature of particle mass in graphene systems

In undulatory mechanics the rest mass of a particle is associated to a rest periodicity known as Compton periodicity. In carbon nanotubes the Compton periodicity is determined geometrically, through dimensional reduction, by the circumference of the curled-up dimension, or by similar spatial constraints to the charge carrier wave function in other condensed matter systems. In this way the Compton periodicity is effectively reduced by several order of magnitudes with respect to that of the electron, allowing for the possibility to experimentally test foundational aspects of quantum mechanics. We present a novel powerful formalism to derive the electronic properties of carbon nanotubes, in agreement with the results known in the literature, from simple geometric and relativistic considerations about the Compton periodicity as well as a dictionary of analogies between particle and graphene physics.Comment: 10 pages, 1 table, 1 figure. Published versio

Weyl states and Fermi arcs in parabolic bands

Weyl fermions are shown to exist inside a parabolic band, where the kinetic energy of carriers is given by the non-relativistic Schroedinger equation. There are Fermi arcs as a direct consequence of the folding of a ring shaped Fermi surface inside the first Brillouin zone. Our results stem from the decomposition of the kinetic energy into the sum of the square of the Weyl state, the coupling to the local magnetic field and the Rashba interaction. The Weyl fermions break the time and reflection symmetries present in the kinetic energy, thus allowing for the onset of a weak three-dimensional magnetic field around the layer. This field brings topological stability to the current carrying states through a Chern number. In the special limit that the Weyl state becomes gapless this magnetic interaction is shown to be purely attractive, thus suggesting the onset of a superconducting condensate of zero helicity states

Counterfactual analysis using a regional dynamic general equilibrium model with historical calibration

This paper develops a regional dynamic general equilibrium model calibrated using two regional SAMs for the Italian region Valle D’Aosta for the years 1963 and 2002. A historical calibration procedure is performed over the 40 years period and a validation exercise ensures that the modelled tendencies closely approximate the actual observed growth patterns of the main regional macroeconomic variables. The dynamic general equilibrium model provides an original and powerful tool for historical counterfactual analysis not available using standard dynamic general equilibrium models. The model is used to compare the growth path followed by the region during the period of interest with different scenarios intended to rank the social desirability of alternative behaviours of the regional administration.historical calibration, historical validation, regional dynamic general equilibrium model, historical counterfactual analysis

Econometric Identification of the Cost of Maintaining a Child

The paper estimates the cost of maintaining a child, of different ages, the cost of being a single and the cost of additional adults present in a family with the aim of making the income levels of different households comparable. The study investigates the issue of econometric identification of equivalence scales within a demand system modified to include demographic characteristics consistently with economic theory. It shows that a robust estimation of equivalence scales must take into formal consideration the problem of econometric identification. The estimation also proposes an encompassing demographic specification which permits isolation of the costs due to differences in needs and differences in household life-styles and scale economies.Equivalence scales, identification, interhousehold comparisons, economies of scale

Curvatronics with bilayer graphene in an effective 4D4D spacetime

We show that in AB stacked bilayer graphene low energy excitations around the semimetallic points are described by massless, four dimensional Dirac fermions. There is an effective reconstruction of the 4 dimensional spacetime, including in particular the dimension perpendicular to the sheet, that arises dynamically from the physical graphene sheet and the interactions experienced by the carriers. The effective spacetime is the Eisenhart-Duval lift of the dynamics experienced by Galilei invariant L\'evy-Leblond spin $\frac{1}{2}$ particles near the Dirac points. We find that changing the intrinsic curvature of the bilayer sheet induces a change in the energy level of the electronic bands, switching from a conducting regime for negative curvature to an insulating one when curvature is positive. In particular, curving graphene bilayers allows opening or closing the energy gap between conduction and valence bands, a key effect for electronic devices. Thus using curvature as a tunable parameter opens the way for the beginning of curvatronics in bilayer graphene.Comment: 8 pages, 3 figures. Revised version with additional materia

Multi-patch model for transport properties of cuprate superconductors

A number of normal state transport properties of cuprate superconductors are analyzed in detail using the Boltzmann equation. The momentum dependence of the electronic structure and the strong momentum anisotropy of the electronic scattering are included in a phenomenological way via a multi-patch model. The Brillouin zone and the Fermi surface are divided in regions where scattering between the electrons is strong and the Fermi velocity is low (hot patches) and in regions where the scattering is weak and the Fermi velocity is large (cold patches). We present several motivations for this phenomenology starting from various microscopic approaches. A solution of the Boltzmann equation in the case of N patches is obtained and an expression for the distribution function away from equilibrium is given. Within this framework, and limiting our analysis to the two patches case, the temperature dependence of resistivity, thermoelectric power, Hall angle, magnetoresistance and thermal Hall conductivity are studied in a systematic way analyzing the role of the patch geometry and the temperature dependence of the scattering rates. In the case of Bi-based cuprates, using ARPES data for the electronic structure, and assuming an inter-patch scattering between hot and cold states with a linear temperature dependence, a reasonable agreement with the available experiments is obtained.Comment: 18 pages, 18 figures, to be published on Eur. Phys. J.