In an article in 2007, Mishra et al. [Phys. Rev. A 76, 013604 (2007)] investigated the two-component Bose-Hubbard model using the numerical density-matrix renormalization-group procedure. In the regime of interspecies repulsion $U^{ab}$ larger than the intraspecies repulsion $U$, they found a transition from a uniform miscible phase to phase separation occurring at a finite value of $U$, e.g., at around $U=1.3$ for $\Delta =U^{ab}/U=1.05$ and ${\rho }_a={\rho }_b=1/2$. In this Comment, we show that this result is not correct, and in fact, the two-component Bose-Hubbard model is unstable to phase separation for any $U^{ab}>U>0$.

• Received 3 January 2014

DOI:https://doi.org/10.1103/PhysRevA.89.057601