QUROPE Quantum Information Processing and Communication in Europe

One of the most important fundamental problems in contemporary physics is to understand the effects of frustration in quantum many-body systems. Typically, frustration is induced by lattice geometries, disorder and/or strong interactions. The resulting states show strong correlations and have exotic properties with possible applications for condensed matter physics, material science, and quantum information technologies, etc. A paradigmatic system that exhibits frustration is a gas of ultracold polar molecules trapped in an optical lattice. Notably, such system is extremely difficult to model theoretically due to proliferation of dipole induced multi-band excitations. In this article we develop for the first time a consistent theoretical model of the polar molecules in a lattice by applying the concepts and ideas of ionization theory. Our approach is necessary for correct account of strong dipolar interaction. Additionally, by merging concepts from quantum optics (population transfer), we show that one can induce frustration and engineer exotic states, such as Majumdar-Ghosh state, or vector-chiral states in such situation. This forms the first attempt to bridge the seemingly two distant areas of research, and opens up a new direction to engineer different strongly-correlated many-body quantum states.