  Although well-researched as a prototype Hamiltonian for strongly interacting
quantum systems, the Bose-Hubbard model has not so far been explored as a fluid
system with waterlike anomalies. In this work we show that this model supports,
in the limit of a strongly localizing confining potential, density anomalies
which can be traced back to ground state (zero-temperature) phase transitions
between different Mott insulators. This key finding opens a new pathway for
theoretical and experimental studies of liquid water and, in particular, we
propose a test of our predictions that can be readily implemented in a
ultra-cold atom platform.
