  The gapless fermionic excitations in superfluid 3He-A have the "relativistic"
spectrum close to the gap nodes. This allowed us to model the modern
cosmological scenaria of baryogenesis and magnetogenesis. The same massless
fermions induce another low-energy property of the quantum vacuum -- the
gravitation. The effective metric of the space, in which the free
quasiparticles move along geodesics, is not generally flat. Different order
parameter textures correspond to curved effective space and produce many
different exotic metrics, which are theoretically discussed in quantum gravity
and cosmology. This includes the condensed matter analog of the black hole and
event horizon, which can be realized in the moving soliton. This will allow us
to simulate and thus experimentally investigate such quantum phenomena as the
Hawking radiation from the horizon, the Bekenstein entropy of the black hole,
and the structure of the quantum vacuum behind the horizon. One can also
simulate the conical singularities produced by cosmic strings and monopoles;
inflation; temperature dependence of the cosmological and Newton constants,
etc.
