Heat transport in solids, beyond the classical approximation – HEATFLOW

The calculations will be based on Kubo formulae that involve time correlation functions to obtain th etransport coefficients. The corresponding correlations can be computed in imaginary time using the PIMC approach. The challenge is to obtain them witj good enough accuracy, so that teh Fourier spectrum can be obtained from imaginary time data. The present approach is to use a maximum entropy method to achieve this aim.

At the moment the method has been applied with success to a toy model (harmonic oscillator). The results appear to be convincing, we hope th emethod will be applicable to more complex cases.

Benchmark onf the method for a toy model.
Perspective: publication of results for the toy model, application to a more complex crystal.

Papers are not ready yet.

The goal of the project HeatFlow is to establish a methodology, based on the formalism of path integrals, allowing one to accurately take into account the influence of nuclear quantum effects on transport properties, and in particular heat transport, in condensed systems. This is a very ambitious task which, be believe, would have profound implications in many research fields, ranging from fundamental physics issues to the development of advanced materials for modern technological applications. We plan to apply the methodology we will develop to a few case studies, involving systems of both fundamental and practical interest in condensed matter science. In particular, we will focus, on one side,
on amorphous systems (glasses) and try to clarify in a plainly first-principles calculations framework the origin of the striking low-temperature anomalies in the thermal properties. On the other side, more in perspective and moving to systems of increased complexity, we will in contrast focus on highly ordered nano-structures, where a careful design with very high spatial resolution can trigger remarkable thermal responses.