lines of fixed points, and phase separation in doped two-dimensional quantum dimer models'
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Introduction {#sec:intro}
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The behavior of doped Mott insulators is a long-standing open and challenging problem in condensed-matter physics. Mott insulators are the parent states of all strongly correlated electronic systems and as such play a crucial role in our understanding of high-$T_c$ superconductors (HTSC) and many other systems. Their strongly correlated nature implies that their behavior cannot be understood in terms of weakly coupled models. Except for the very special case of one spatial dimension, the physics of doped Mott insulators is currently only understood at a qualitative level. The solution of this challenging problem remains one of the most important directions of research in condensed-matter physics.

Quantum dimer models (QDM)[@rokhsar88] provide a simplified, and rather crude, description of the physics of a Mott insulator. They provide a correct description of the physics of Mott insulators in regimes in which the spin excitations have a large spin gap. QDMs were proposed originally within the context of the resonating-valence bond (RVB) mechanism of HTSC.[@anderson87; @kivelson87] These systems are of great interest as they can yield hints on the behavior of more realistic models of quantum frustration.

