Bad Honnef. With current developments in technology and research, structures are now being investigated and utilised that are far smaller than the characteristic length scales on which the textbook laws for thermal radiation and phononic heat conduction - such as Planck's radiation law and Fourier's law - are valid. This makes it necessary to develop completely new methods of investigation and description in order to understand thermal radiation and heat conduction phenomena on nanometric length scales as well. The WE-Heraeus seminar from 11 to 15 April 2016 in Bad Honnef was dedicated to this highly topical subject.

The aim was to provide a detailed introduction to the basic theories and experiments as well as an overview of the current state of research. Introductory contributions presented both the theories of fluctuating electrodynamics and macroscopic quantum electrodynamics as well as a whole range of experimental methods that make it possible to characterise thermally fluctuating electromagnetic near fields in a wide variety of ways and to investigate photonic and phonic heat conduction in a wide range of nano- and microstructures. In addition to analytical models, numerical simulation techniques were presented which, with the aid of new mathematical methods, make it possible to describe heat flows even for highly complex geometries on nanometric length scales. The knowledge gained can be utilised in a wide range of applications. For example, they help to improve thermoelectric energy converters and microcoolers. There are also proposals for completely new types of thermal components such as diodes, transistors and even memories based on phase transition materials or quantum systems.

A total of seventy-five participants from eighteen nations and four continents came to Bad Honnef to listen to thirty-three presentations (twenty of which were invited) and to discuss them at length. In addition, twenty-four posters were presented and lively discussed in three poster sessions. As can be seen from these figures, the seminar was intensive; the response from colleagues was very positive. In particular, they were very impressed by the facilities and premises of the Physikzentrum as well as the organisation and support from the WE-Heraeus Foundation, which we would like to take this opportunity to thank once again.