Novel Polaron State for Single Impurity in a Bosonic Mott Insulator
  We show that a single impurity embedded in a cold atom bosonic Mott insulator leads to a novel polaron that exhibits correlated motion with an effective mass and a linear size that nearly diverge at critical value of the on-site impurity-boson interaction strength. Cold atom technology can tune the polaron's properties and break up the composite particle into a deconfined impurity-hole and boson particle state at finite, controllable polaron momentum. 
Yasuyuki Kato, K. A. Al-Hassanieh, A. E. Feiguin, Eddy Timmermans and   C. D. Batista
cond-mat.quant-gas cond-mat.supr-con