Discoveries of superfluid phases in 3He, high Tc superconductors, graphene and topological insulators have brought into focus materials where quasiparticles are described by same Dirac equation that governs behaviour of relativistic particles. This class of materials – Dirac materials – exhibits unusual universal features seen in numerous realizations: Klein tunnelling, chiral symmetries and impurity resonances. Research at Nordita has explored these similarities and discussed the unique role of symmetries that protect the Dirac spectrum, and how to control their properties. Modern tools have been used to design artificial Dirac Materials, for example Bosonic Dirac materials that host bosonic Dirac excitations, something that is not possible in particle physics where the Dirac excitations are fermionic.
Dirac matter is a general concept, the research pages provide more detail of the particular interests of the research group; a more general overview may be found on Wikipedia.
Research falls into several areas:
Pumped Dirac Materials: Recent pump-probe experiments demonstrate the possibility that Dirac materials may be driven into transient excited states describable by two chemical potentials, one for the electrons and one for the holes. Given the Dirac nature of the spectrum, such an inverted population allows the optical tunability of the density of states of the electrons and holes, effectively offering control of the strength of the Coulomb interaction.
Transport and other properties: The study of systems such as graphene and topological insulators with a view to their applications requires a detailed understanding of their properties even in equilibrium. In particular, transport and the motion and behaviour of the Dirac (quasi-)particles in reaction to potentials of different types and composite systems are of particular importance.