Weyl and flat-band fermions in topological superfluids

The focus of the proposal is experimental investigations of topological matter at ultra-low temperatures. The name refers to macroscopic quantum systems with topologically non-trivial ground states, like topological insulators, Weyl semimetals or superfluid phases of the 3He isotope. Although these materials are built from regular atoms, theory predicts that their low-temperature properties are described in terms of exotic massless particles. In future such materials promise to change everyday life by making quantum devices available even at room temperatures, but currently there is still a lot of questions to answer. We propose to achieve the best understanding and agreement with the theory in clean 3He superfluids. We plan to find out how massless fermions in 3He interact with the rest of the system and control the dynamic properties of topological matter. Resolving this question is of crucial importance for future applications in inevitably dynamic noisy environment.