ترغب بنشر مسار تعليمي؟ اضغط هنا

Fourier law from a chain of coupled anharmonic oscillators under energy conserving noise

343   0   0.0 ( 0 )
 نشر من قبل Gabriel Landi Dr.
 تاريخ النشر 2013
  مجال البحث فيزياء
والبحث باللغة English




اسأل ChatGPT حول البحث

We analyze the transport of heat along a chain of particles interacting through anharmonic po- tentials consisting of quartic terms in addition to harmonic quadratic terms and subject to heat reservoirs at its ends. Each particle is also subject to an impulsive shot noise with exponentially distributed waiting times whose effect is to change the sign of its velocity, thus conserving the en- ergy of the chain. We show that the introduction of this energy conserving stochastic noise leads to Fourier law. The behavior of thels heat conductivity for small intensities of the shot noise and large system sizes are found to obey a finite-size scaling relation. We also show that the heat conductivity is not constant but is an increasing monotonic function of temperature.



قيم البحث

اقرأ أيضاً

We study the transport of heat along a chain of particles interacting through a harmonic potential and subject to heat reservoirs at its ends. Each particle has two degrees of freedom and is subject to a stochastic noise that produces infinitesimal c hanges in the velocity while keeping the kinetic energy unchanged. This is modelled by means of a Langevin equation with multiplicative noise. We show that the introduction of this energy conserving stochastic noise leads to Fouriers law. By means of an approximate solution that becomes exact in the thermodynamic limit, we also show that the heat conductivity $kappa$ behaves as $kappa = a L/(b+lambda L)$ for large values of the intensity $lambda$ of the energy conserving noise and large chain sizes $L$. Hence, we conclude that in the thermodynamic limit the heat conductivity is finite and given by $kappa=a/lambda$.
Systems in which the heat flux depends on the direction of the flow are said to present thermal rectification. This effect has attracted much theoretical and experimental interest in recent years. However, in most theoretical models the effect is fou nd to vanish in the thermodynamic limit, in disagreement with experiment. The purpose of this paper is to show that the rectification may be restored by including an energy-conserving noise which randomly flips the velocity of the particles with a certain rate $lambda$. It is shown that as long as $lambda$ is non-zero, the rectification remains finite in the thermodynamic limit. This is illustrated in a classical harmonic chain subject to a quartic pinning potential (the $Phi^4$ model) and coupled to heat baths by Langevin equations.
118 - Isao Nishikawa , Gouhei Tanaka , 2013
Universal scaling laws form one of the central issues in physics. A non-standard scaling law or a breakdown of a standard scaling law, on the other hand, can often lead to the finding of a new universality class in physical systems. Recently, we foun d that a statistical quantity related to fluctuations follows a non-standard scaling law with respect to system size in a synchronized state of globally coupled non-identical phase oscillators [Nishikawa et al., Chaos $boldsymbol{22}$, 013133 (2012)]. However, it is still unclear how widely this non-standard scaling law is observed. In the present paper, we discuss the conditions required for the unusual scaling law in globally coupled oscillator systems, and we validate the conditions by numerical simulations of several different models.
177 - Cedric Bernardin 2014
We consider a harmonic chain perturbed by an energy conserving noise and show that after a space-time rescaling the energy-energy correlation function is given by the solution of a skew-fractional heat equation with exponent 3/4.
We theoretically study energy pumping processes in an electrical circuit with avalanche diodes, where non-Gaussian athermal noise plays a crucial role. We show that a positive amount of energy (work) can be extracted by an external manipulation of th e circuit in a cyclic way, even when the system is spatially symmetric. We discuss the properties of the energy pumping process for both quasi-static and fnite-time cases, and analytically obtain formulas for the amounts of the work and the power. Our results demonstrate the significance of the non-Gaussianity in energetics of electrical circuits.
التعليقات
جاري جلب التعليقات جاري جلب التعليقات
mircosoft-partner

هل ترغب بارسال اشعارات عن اخر التحديثات في شمرا-اكاديميا