  We use large scale quantum Monte-Carlo simulations to study an extended
Hubbard model of hardcore bosons on the kagome lattice. In the limit of strong
nearest-neighbor interactions at 1/3 filling, the interplay between frustration
and quantum fluctuations leads to a valence bond solid ground state. The system
undergoes a quantum phase transition to a superfluid phase as the interaction
strength is decreased. It is still under debate whether the transition is
weakly first order or represents an unconventional continuous phase transition.
We present a theory in terms of an easy-plane NCCP$^1$ gauge theory describing
the phase transition at 1/3 filling. Utilizing large scale quantum Monte-Carlo
simulations with parallel tempering in the canonical ensemble up to 15552
spins, we provide evidence that the phase transition is continuous at exactly
1/3 filling. A careful finite size scaling analysis reveals an unconventional
scaling behavior hinting at deconfined quantum criticality.
