Wage bargaining and quality competition

In a standard model of vertical differentiation, wage is assumed to determine the quality. Wage is also subject to bargaining. Increased bargaining power of the worker in the low quality firm reduces quality differential, and increases price competitiveness. The Opposite happens from a similar change in the high quality firm.Wage bargaining; Quality competition

Ground state phase diagram and magnetoconductance of a one-dimensional Hubbard superlattice at half-filling

We have studied a one dimensional Hubbard superlattice with different Coulomb correlations at alternating sites for a half-filled band. Mean field calculations based on the Hartree-Fock approximation together with a real space renormalization group technique were used to study the ground state of the system. The phase diagrams obtained in these approaches agree with each other from the weak to the intermediate coupling regime. The mean field results show very quick convergence with system size. The renormalization group results indicate a spatial modulation of local moments that was identified in some previous work. Also we have studied the magnetoconductance of such superlattices which reveals several interesting points.Comment: 10 pages, 13 figures. to be published in Phys. Rev. B, vol. 75, Issue 23 (tentative

Wage bargaining and quality competition

In a standard model of vertical differentiation, wage is assumed to determine the quality. Wage is also subject to bargaining. Increased bargaining power of the worker in the low quality firm reduces quality differential, and increases price competitiveness. The Opposite happens from a similar change in the high quality firm

Wage bargaining and quality competition

In a standard model of vertical differentiation, wage is assumed to determine the quality. Wage is also subject to bargaining. Increased bargaining power of the worker in the low quality firm reduces quality differential, and increases price competitiveness. The Opposite happens from a similar change in the high quality firm

Effect of external electric field on the charge density waves in one dimensional Hubbard superlattices

We have studied the ground state of the one dimensional Hubbard superlattice structures with different unit cell sizes in the presence of electric field. Self consistent Hartree-Fock approximation calculation is done in the weak to intermediate interaction regime. Studying the charge gap at the Fermi level and the charge density structure factor, we get an idea how the charge modulation on the superlattice is governed by the competition between the electronic correlation and the external electric field.Comment: 6 pages, 8 figures. accepted in Journal of Physics: Condensed Matte

Effect of Fibonacci Modulation On Superconductivity

We have studied finite-sized single band models with short range pairing interactions between electrons in presence of diagonal Fibonacci modulation in one dimension. Two models, namely the attractive Hubbard model and the Penson-Kolb model, have been investigated at half-filling at zero temperature by solving the Bogoliubov-de Gennes equations in real space within a mean field approximation. The competition between ``disorder'' and the pairing interaction leads to a suppression of superconductivity (of usual pairs with zero centre-of-mass momenta) in the strong-coupling limit while an enhancement of the pairing correlation is observed in the weak-coupling regime for both the models. However, the dissimilarity of the pairing mechanisms in these two models brings about notable difference in the results. The extent to which the bond ordered wave and the $\eta$-paired (of pairs with centre-of-mass momenta = $\pi$) phases of the Penson-Kolb model are affected by the disorder has also been studied in the present calculation. Some finite size effects are also identified.Comment: 14 pages, 13 figure

Spektroskopska mjerenja prijelaza D2 Rb u ovisnosti o temperaturi i snazi sa i bez Dopplerovog efekta

An external-cavity diode-laser spectrometer has been set up for high-resolution measurement of line shapes of the RbD2 transitions. Temperature-dependent fine-structure measurements are carried out in a free-running temperature condition by using frequency ramps for repetitive current tuning over a region of 17 GHz, encompassing all of the four Doppler broadened transitions of the two isotopes in an almost collision-free region. The Doppler broadened widths extracted from temperature-dependent line shapes, on least squares fitting to observed data, lead to an estimation of root-means-square velocities of vapour atoms under varying temperature conditions. Saturated-absorption spectroscopic measurements show complete resolution of the hyperfine Lamb dips and crossover resonance dips of one 87RbD2 transition. Data recorded from power-dependent measurement of one of unresolved 85RbD2 transitions are analyzed to obtain the saturation parameter and power broadening coefficient. The linewidths of different fully resolved Lamb dips of the hyperfine and crossover-resonance components are not the same, suggesting differences in their natural linewidths.Pomoću diodnog lasera s vanjskim rezonatorom načinili smo mjerenja oblika linija prijelaza D2 Rb. Mjerenja temperaturne ovisnosti fine strukture izveli smo u uvjetima slobodno promjenljive temperature, upotrebom frekventne rampe za ponavljanje struje, podešene za područje 17 GHz koje obuhvaća sva četiri Dopplerovim efektom proširena prijelaza dvaju izotopa Rb u uvjetima gotovo bez sudara. Širenje linija Dopplerovim efektom u ovisnosti o temperaturi, utvrđeno metodom najmanjih kvadrata, daje korijene iz srednjih kvadrata brzina atoma u parama. Spektroskopska mjerenja sa zasićenom apsorpcijom pokazuju potpuno razlučivanje hiperfinih Lambovih i preskočnih rezonantnih minimuma prijelaza D2 87Rb. Podatke iz mjerenja ovisnosti o snazi za nerazlučeni prijelaz D2 85Rb smo analizirali radi dobivanja parametara zasićenja i koeficijenta širenja sa snagom. Širine potpuno razlučenih linija hiperfinih Lambovih i preskočnih rezonantnih minimuma nisu jednake, što ukazuje na različitost njihovih prirodnih širina

Spektroskopska mjerenja prijelaza D2 Rb u ovisnosti o temperaturi i snazi sa i bez Dopplerovog efekta

An external-cavity diode-laser spectrometer has been set up for high-resolution measurement of line shapes of the RbD2 transitions. Temperature-dependent fine-structure measurements are carried out in a free-running temperature condition by using frequency ramps for repetitive current tuning over a region of 17 GHz, encompassing all of the four Doppler broadened transitions of the two isotopes in an almost collision-free region. The Doppler broadened widths extracted from temperature-dependent line shapes, on least squares fitting to observed data, lead to an estimation of root-means-square velocities of vapour atoms under varying temperature conditions. Saturated-absorption spectroscopic measurements show complete resolution of the hyperfine Lamb dips and crossover resonance dips of one 87RbD2 transition. Data recorded from power-dependent measurement of one of unresolved 85RbD2 transitions are analyzed to obtain the saturation parameter and power broadening coefficient. The linewidths of different fully resolved Lamb dips of the hyperfine and crossover-resonance components are not the same, suggesting differences in their natural linewidths.Pomoću diodnog lasera s vanjskim rezonatorom načinili smo mjerenja oblika linija prijelaza D2 Rb. Mjerenja temperaturne ovisnosti fine strukture izveli smo u uvjetima slobodno promjenljive temperature, upotrebom frekventne rampe za ponavljanje struje, podešene za područje 17 GHz koje obuhvaća sva četiri Dopplerovim efektom proširena prijelaza dvaju izotopa Rb u uvjetima gotovo bez sudara. Širenje linija Dopplerovim efektom u ovisnosti o temperaturi, utvrđeno metodom najmanjih kvadrata, daje korijene iz srednjih kvadrata brzina atoma u parama. Spektroskopska mjerenja sa zasićenom apsorpcijom pokazuju potpuno razlučivanje hiperfinih Lambovih i preskočnih rezonantnih minimuma prijelaza D2 87Rb. Podatke iz mjerenja ovisnosti o snazi za nerazlučeni prijelaz D2 85Rb smo analizirali radi dobivanja parametara zasićenja i koeficijenta širenja sa snagom. Širine potpuno razlučenih linija hiperfinih Lambovih i preskočnih rezonantnih minimuma nisu jednake, što ukazuje na različitost njihovih prirodnih širina