Seminars Archive

Temperature wave properties and wave propagation in a Temperonic Crystal

Abstract
To describe the thermal dynamics of an object subject to a temperature gradient, in the 19th Century Fourier introduced its famous law. Fourier’s Law relates the temperature to the heat flux within an object. Despite being a milestone in thermodynamics, and its widespread use in every day applications, Fourier's Law is not correct. Fourier’s Law implies the heat flux and the temperature gradient to be simultaneous, leading to an infinite propagation speed for the heat flux. This inconsistency is not appreciated at the macroscale but may emerge on “short” space/time scales, the latter being reachable thanks to recent advances in nanotechnology and time-resolved experiments. Several attempts have been made to correct this law, the most notable examples being the Cattaneo-Vernotte (CV)1 and the Dual-Phase-Lag (DPL)2 models. These models predict the temperature to have waves properties. In this talk, theoretical in nature, I will introduce the Dual-Phase-Lag model and, building on this rationale, I will suggest exploiting the wave properties of the temperature scalar field on the “short” space/time scale to control a temperature wave packet. In particular I will introduce the concept of a Temperonic Crystal, a metamaterial composed by a periodic alternation of materials having different thermal properties, and its possible application as a filter of temperature’s wave frequencies. 1-Reviews of Modern Physics, Vol. 61, No. 1, January 1989, pag 41.
 2-D. Y. Tzou, Macro- to Microscale Heat Transfer, The Lagging Behavior, Second Edition, John Wiley & Sons, Ltd., 2015, pages 25-30.