Perex
Abstract:
Recent experiments have shown that (quasi-)crystalline phases of Rydberg-dressed quantum many body systems in optical lattices (OL) are within reach. While conventional neutral atomic OL gases lack strong long-range interactions, they arise naturally in Rydberg systems, due to the large polarisability of Rydberg atoms. In combination with the bosonic character of these systems, a wide range of quantum phases have been predicted. Among them are a devil’s staircase of lattice-incommensurate density wave states, as well as more exotic supersolid lattice order.
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High experimental tunability opens up a wide range of parameters to be studied. We study the ground state phase diagram at finite hopping amplitudes and in the vicinity of resonant Rydberg driving. Since different types of lattice-incommensurate order are to be expected, we apply a real-space extension of bosonic dynamical mean-field theory (BDMFT). This method allows a non-perturbative treatment of local quantum correlations and yields a rich phase diagram, illustrating the competition between interaction and condensation. We furthermore investigate strongly correlated spin-1 ultracold bosons with antiferromagnetic interactions in a cubic optical lattice, based on BDMFT. Rich phase diagrams of the system are mapped out at both zero and finite temperature, and in particular the existence of a spin-singlet condensate is established. At finite temperature, we find that the superfluid can be heated into a Mott insulator, analogous to the Pomeranchuk effect in He_3.