We present a scalable method for generation of a cluster state for measurement-based quantum computing using van der Waals or dipole-dipole interactions between neutral atoms or polar molecules in an optical lattice. Nearest neighbor entanglement is accomplished by performing a phase gate using interaction of atoms in Rydberg states or molecules in large dipole moment states. All nearest neighbors are sequentially entangled in a finite number of operations, independent of the number of qubits, producing a one-dimensional (1D) cluster state. A universal two-dimensional (2D) cluster state can be generated in several milliseconds in a 2D optical lattice by producing a series of 1D cluster states in one lattice direction, followed by application of the entangling operations in another lattice direction. We discuss the viability of the scheme with Rb Rydberg atoms.
We report the hyperfine coupling constants for the 6d 2 D J states of 133 Cs using two-color absorption spectroscopy with sub-Doppler resolution. Two single-mode diode lasers resonantly excite cesium in a low-pressure vapor cell. The frequency scale is directly referenced to the ground hyperfine interval of 87 Rb using a radiofrequency modulation technique. The 6d 2 D 5/2 coupling constants are measured as A = −4.66± 0.04 MHz and B = 0.9± 0.8 MHz, agreeing with the literature. The 6d 2 D 3/2 coupling constants are measured as A = 16.34± 0.03 MHz and B = −0.1± 0.2 MHz, which significantly improve the precision of previous measurements.
We model single photon nonlinearities resulting from the dipole-dipole interactions of cold polar molecules. We propose utilizing "dark state polaritons" to effectively couple photon and molecular states; through this framework, coherent control of the nonlinearity can be expressed and potentially used in an optical quantum computation architecture. Due to the dipole-dipole interaction the photons pick up a measurable nonlinear phase even in the single photon regime. A manifold of protected symmetric eigenstates is used as basis. Depending on the implementation, major sources of decoherence result from non-symmetric interactions and phonon dispersion. We discuss the strength of the nonlinearity per photon and the feasibility of this system.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.