  Thermodynamically, bosons and fermions differ by their statistics only. A
general entropy functional is proposed by superposition of entropic terms,
typical for different quantum gases. The statistical properties of the
corresponding Janus particles are derived by variation of the weight of the
boson/fermion fraction. It is shown that di-bosons and anti-fermions separate
in gas and liquid phases, while three-phase equilibrium appears for
poly-boson/fermion Janus particles.
