Mott insulators are central to the physics of strongly correlated electron systems. If the normal state of the system is a Fermi liquid, characterized by the well defined quasiparticles, the Mott insulator formed after introducing strong enough background lattice can be qualitatively understood as a "traffic jam" of these repulsive quasi-electrons.
But what if the normal state is instead the densely entangled strange metal, where quasipaticles are not identifiable anymore? Then one gets the most notorious Mott insulator, observed in under-doped cuprate high-Tc superconductors. This state violates some of the simple logic which follows from classical "traffic jam" picture.
The holographic duality, discovered in string theory, describes generic properties of certain classes of such densely entangled quantum matter. Using holography, we build the "strange metal" version of the Mott insulator as a commensurate state between spontaneous intertwined charge density wave and a lattice. We show that this state shares many properties with the conventional Mott insulator, but is different in several aspects. Crucially, these differences can shed light on the unconventional features of the Mott state in the under-doped cuprate.
Based on: arXiv:1710.05791