We investigate photonic energy and heat transport in nanoscopic systems employing different analytical methods. On the one hand, we use the semiclassical theory of fluctuating electrodynamics. On the other hand, we also apply purely quantum mechanical or quantum optical theories such as the theory of open quantum systems and macroscopic quantum electrodynamics. What all these theories have in common is that they can be combined with the method of dyadic Green's functions, which enables us to investigate energy and heat transport in realistic environments and nanosystems.

One focus of our research is near-field heat transfer or thermal radiation in the nanometer range. In this range, the usual laws of thermal radiation, such as Planck's radiation law, no longer apply. In recent decades, many of the newly discovered laws of thermal radiation have been confirmed experimentally for a wide variety of materials down to distances of a few nanometers. Currently, the heat transport in topological and non-reciprocal many-body systems is at the center of our research interest. An overview of this topic can be found in the review article

S.-A. Biehs, R. Messina, P. S. Venkataram, A. W. Rodriguez, J. C. Cuevas, and P. Ben-Abdallah:
Near-field radiative heat transfer in many-body systems, 
Rev. Mod. Phys. 93, 025009 (2021).

Furthermore, we deal with energy transport and entanglement of quantum systems coupled to dissipative plasmonic environments, but also with Casimir forces and classical nano-optical questions.