In the present work we demonstrate how to realize a 1D closed optical lattice experimentally, including a tunable boundary phase twist. The latter may induce "persistent currents" visible by studying the atoms' momentum distribution. We show how important phenomena in 1D physics can be studied by physical realization of systems of trapped atoms in ring-shaped optical lattices. A mixture of bosonic and/or fermionic atoms can be loaded into the lattice, realizing a generic quantum system of many interacting particles.
The advent of increasingly precise gyroscopes has played a key role in the technological development of navigation systems. Ring-laser and fiber-optic gyroscopes, for example, are widely used in modern inertial guidance systems and rely on the interference of unentangled photons to measure mechanical rotation. The sensitivity of these devices scales with the number of particles used as 1/N. Here we demonstrate how, by using sources of entangled particles, it is possible to do better and even achieve the ultimate limit allowed by quantum mechanics where the precision scales as 1/N. We propose a gyroscope scheme that uses ultracold atoms trapped in an optical ring potential.
The quantum dynamics of particles optically trapped in a symmetrically pumped high-Q ring cavity exhibits much richer physics than for a standing-wave resonator. In addition to modifying the lattice depth, light scattering by the particles shifts and reshapes the trapping potential. We calculate the corresponding changes in tunneling amplitudes and damping by an effective bipotential (two-level) model for the particle motion. As a crude truncation of the Bose-Hubbard model, expansion to the lowest band decouples particle and field dynamics. Only including excitations to higher bands can capture this essential additional physics and correctly describe decoherence, damping, and long-range correlations of the particle dynamics. The validity limits of the analytic models are confirmed by quantum Monte Carlo wave-function simulations, which exhibit correlated particle-field quantum jumps as unambiguous quantum signature of the system dynamics.