13,416 research outputs found
Phase separation in quasi incompressible fluids: Cahn-Hilliard model in the Cattaneo-Maxwell framework
In this paper we propose a mathematical model of phase separation for a
quasi-incompressible binary mixture where the spinodal decomposition is induced
by an heat flux governed by the Cattaneo-Maxwell equation. As usual, the phase
separation is considered in the framework of phase field modeling so that the
transition is described by an additional field, the concentration c. The
evolution of concentration is described by the Cahn-Hilliard equation and in
our model is coupled with the Navier-Stokes equation. Since thermal effect are
included, the whole set of evolution equations is set up for the velocity, the
concentration, the temperature and the heat flux. The model is compatible with
thermodynamics and a maximum theorem holds.Comment: Submitted to ZAM
Business Cycles in Emerging Economies: The Role of Interest Rates
We find that in a sample of emerging economies business cycles are more volatile than in developed ones, real interest rates are countercyclical and lead the cycle, consumption is more volatile than output and net exports are strongly countercyclical. We present a model of a small open economy, where the real interest rate is decomposed in an international rate and a country risk component. Country risk is affected by fundamental shocks but, through the presence of working capital, also amplifies the effects of those shocks. The model generates business cycles consistent with Argentine data. Eliminating country risk lowers Argentine output volatility by 27% while stabilizing international rates lowers it by less than 3%.
Comment on ``Enhancement of the Tunneling Density of States in Tomonaga-Luttinger Liquids''
In a recent Physical Review Letter, Oreg and Finkel'stein (OF) have
calculated the electron density of states (DOS) for tunneling into a repulsive
Luttinger liquid close to the location of an impurity. The result of their
calculation is a DOS which is enhanced with respect to the pure system, and
moreover diverging for not too strong repulsion. In this Comment we intend to
show that OF's calculation suffers from a subtle flaw which, being corrected,
results into a DOS not only vanishing at zero frequency but in fact suppressed
in comparison with the DOS of a pure Luttinger liquid.Comment: 1 page, Revte
Reply to the Comment on "Enhancement of the Tunneling Density of States in Tomonaga-Luttinger Liquids"
In their comment Fabrizio and Gogolin dispute our result of the enhancement
of the tunneling density of states in a Tomonaga-Luttinger liquid at the
location of a backward scattering defect [Phys. Rev. Lett. 76, 4230(1996);
cond-mat/9601020]. They state that the anticommutativity of the fermion
operators of the left and right moving electrons was not considered properly in
the Letter. We show in the Reply that the result of the Letter can be
reproduced following the Comment when its calculations are performed correctly.
This clearly indicates that the question about the anticommutation relations
was raised by Fabrizio and Gogolin without serious grounds.Comment: Published in PRL as a Reply to the Comment by Fabrizio and Gogolin
(cond-mat/9702080
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