Superfluid analogies of cosmological phenomena

In a modern viewpoint relativistic quantum field theory is an emergent phen omenon arising in the low-energy corner of the physical fermionic vacuum - the medium, whose nature remains unknown. The same phenomenon occurs in con densed matter systems: In the extreme limit of low-energy condensed matter systems of special universality class acquire all the symmetries, which we know today in high-energy physics: Lorentz invariance, gauge invariance, ge neral covariance, etc. The chiral fermions as well as gauge bosons and grav ity field arise as fermionic and bosonic collective modes of the system. In homogeneous states of the condensed matter ground state - vacuum - induce n ontrivial effective metrics of the space, where the free quasiparticles mov e along geodesics. This conceptual similarity between condensed matter and the quantum vacuum allows us to simulate many phenomena in high-energy phys ics and cosmology, including the axial anomaly, baryoproduction and magneto genesis, event horizon and Hawking radiation, cosmological constant and rot ating vacuum, etc., probing these phenomena in ultra-low-temperature superf luid helium, atomic Bose condensates and superconductors. Some of the exper iments have been already conducted. (C) 2001 Elsevier Science B.V. All righ ts reserved.