Towards phase-coherent caloritronics in superconducting quantum circuits

The emerging field of coherent caloritronics (from the Latin word „calor“, i.e., heat) is based on the possibility to manipulate the phase-coherent heat currents flowing in mesoscopic superconducting structures. The goal is to design and implement quantum technologies able to master energy transfer with the same degree of accuracy reached for charge transport in contemporary electronic devices. This can be obtained by exploiting the macroscopic quantum coherence intrinsic to superconducting condensates, which manifests itself through the Josephson and the proximity effect. Here, we review recent experimental results obtained in the realization of heat interferometers and thermal rectifiers, and discuss a few proposals for exotic non-linear phase-coherent caloritronic devices, such as thermal transistors, solid-state memories, coherent heat splitters, microwave refrigerators, thermal engines and heat valves. Besides being extremely attractive from the fundamental physics point of view, these systems are expected to have a vast impact on all cryogenic microcircuits requiring energy management, and (possibly) lay the first stone for the foundation of electronic thermal logic.