3 research outputs found
Nonequilibrium dynamics of a stochastic model of anomalous heat transport: numerical analysis
We study heat transport in a chain of harmonic oscillators with random
elastic collisions between nearest-neighbours. The equations of motion of the
covariance matrix are numerically solved for free and fixed boundary
conditions. In the thermodynamic limit, the shape of the temperature profile
and the value of the stationary heat flux depend on the choice of boundary
conditions. For free boundary conditions, they also depend on the coupling
strength with the heat baths. Moreover, we find a strong violation of local
equilibrium at the chain edges that determine two boundary layers of size
(where is the chain length), that are characterized by a
different scaling behaviour from the bulk. Finally, we investigate the
relaxation towards the stationary state, finding two long time scales: the
first corresponds to the relaxation of the hydrodynamic modes; the second is a
manifestation of the finiteness of the system.Comment: Submitted to Journal of Physics A, Mathematical and Theoretica
A stochastic model of anomalous heat transport: analytical solution of the steady state
We consider a one-dimensional harmonic crystal with conservative noise, in
contact with two stochastic Langevin heat baths at different temperatures. The
noise term consists of collisions between neighbouring oscillators that
exchange their momenta, with a rate . The stationary equations for the
covariance matrix are exactly solved in the thermodynamic limit ().
In particular, we derive an analytical expression for the temperature profile,
which turns out to be independent of . Moreover, we obtain an exact
expression for the leading term of the energy current, which scales as
. Our theoretical results are finally found to be consistent
with the numerical solutions of the covariance matrix for finite .Comment: Minor changes in the text. To appear in Journal of Physics
Etude de la photodissociation de l'ozone par une methode dependant du temps
SIGLEAvailable from INIST (FR), Document Supply Service, under shelf-number : T 78316 / INIST-CNRS - Institut de l'Information Scientifique et TechniqueFRFranc