  Localization in interacting systems caused by disorder, known as many-body
localization (MBL), has attracted a lot of attention in recent years. Most
systems studied in this context also show single-particle localization, and the
question of MBL is whether the phenomena survives the effects of interactions.
It is intriguing to consider a system with no single-particle localization but
which does localize in the presence of many particles. The localization
phenomena occurs "due to" rather than "in spite of" interactions in such
systems. We consider a simple bosonic system and show that interactions enhance
the effects of very weak disorder and result in localization when many
particles are present. We provide physical insights into the mechanism involved
and support our results with analytical and numerical calculations.
