Thermal memristor and neuromorphic networks for manipulating heat flow

A memristor is one of four fundamental two-terminal solid elements in electronics. In addition with the resistor, the capacitor and the inductor, this passive element relates the electric charges to current in solid state elements. Here we report the existence of a thermal analog for this element made with metal-insulator transition materials. We demonstrate that these memristive systems can be used to create thermal neurons opening so the way to neuromophic networks for smart thermal management and information treatment

Thermal photon drag in many-body systems

We demonstrate the existence of a thermal analog of Coulomb drag in many-body systems which is driven by thermal photons. We show that this frictional effect can either be positive or negative depending on the separation distances within the system. Also we highlight that the persistent heat currents flowing in non-reciprocal systems at equilibrium are subject to this effect and the latter can even amplify these flows

Analysis of a diffusive effective mass model for nanowires

We propose in this paper to derive and analyze a self-consistent model describing the diffusive transport in a nanowire. From a physical point of view, it describes the electron transport in an ultra-scaled confined structure, taking in account the interactions of charged particles with phonons. The transport direction is assumed to be large compared to the wire section and is described by a drift-diffusion equation including effective quantities computed from a Bloch problem in the crystal lattice. The electrostatic potential solves a Poisson equation where the particle density couples on each energy band a two dimensional confinement density with the monodimensional transport density given by the Boltzmann statistics. On the one hand, we study the derivation of this Nanowire Drift-Diffusion Poisson model from a kinetic level description. On the other hand, we present an existence result for this model in a bounded domain

The dynamic effects of countercyclical fiscal stimulus on output in Tunisia

With the global financial crisis hitting many countries, policymakers around the world have been weighing different countercyclical policies to support aggregate demand and restore growth. The analysis in this paper estimates a Structural Vector Error Correction model for Tunisia in order to identify the impact of fiscal policy shocks on real output. The authors find that public investment has a small impact on output in the short run but is an important medium-term growth-enhancing countercyclical instrument that has a robust impact on growth. Raising public investment by 1 dinar yields 0.12 dinar the first year, 0.30 dinar the second year, half a dinar the third year, and 1.08 dinars the sixth year. An increase in recurrent expenditure has a smaller but positive and persistent impact on real output. For Tunisia to obtain a larger short-term impact of public spending on output, procurement processes should be made faster and simpler. Finally, the analysis finds a countercyclical pattern of real public investment vis-à-vis real output and a relative rigidity/inelasticity of recurrent expenditures to output fluctuations.Debt Markets,Economic Stabilization,Economic Theory&Research,Emerging Markets,Investment and Investment Climate

Contactless heat flux control with photonic devices

The ability to control electric currents in solids using diodes and transistors is undoubtedly at the origin of the main developments in modern electronics which have revolutionized the daily life in the second half of 20th century. Surprisingly, until the year 2000 no thermal counterpart for such a control had been proposed. Since then, based on pioneering works on the control of phononic heat currents new devices were proposed which allow for the control of heat fluxes carried by photons rather than phonons or electrons. The goal of the present paper is to summarize the main advances achieved recently in the field of thermal energy control with photons.Comment: Invited Revie

On Super-Planckian thermal emission in far field regime

We study, in the framework of the Landauer theory, the thermal emission in far-field regime, of arbitrary indefinite planar media and finite size systems. We prove that the flux radiated by the former is bounded by the blackbody emission while, for the second, there is in principle, no upper limit demonstrating so the possibility for a super-Planckian thermal emission with finite size systems