  This article reviews some recent developments for new cooling technologies in
the fields of condensed matter physics and cold gases, both from an
experimental and theoretical point of view. The main idea is to make use of
distinct many-body interactions of the system to be cooled which can be some
cooling stage or the material of interest itself, as is the case in cold gases.
For condensed matter systems, we discuss magnetic cooling schemes based on a
large magnetocaloric effect as a result of a nearby quantum phase transition
and consider effects of geometrical frustration. For ultracold gases, we review
many-body cooling techniques, such as spin-gradient and Pomeranchuk cooling,
which can be applied in the presence of an optical lattice. We compare the
cooling performance of these new techniques with that of conventional
approaches and discuss state-of-the-art applications.
