Trapped cold atoms systems have emerged as a new frontier of research in condensed matter physics. In particular, physics associated with strong interactions in such systems is of strong current interest. In this talk I will describe several examples in which quantum phase transitions and emergent particles with exotic properties arise in such systems, which do not have counter parts in traditional electronic condensed matter systems. These include: (i) the possibility of realizing supersymmetry in Bose-Fermi mixtures, and detecting a Goldstone fermion called Goldstino in such systems; (ii) a new universality class of superfluid-insulator transition in >Bose-Fermi mixtures, and high-Tc p-wave fermion pairing mediated by quantum critical fluctuations; and (iii) quantum phase transitions
from integer quantum Hall phases to a fractional quantum Hall phases
driven by attractive interactions, where the critical theory is that of a massless relativistic semion in one case, and a Z2 gauge theory in the other.