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Let Γ q denote the q-th stage of the descending central series of the free group on n generators F n. For each q ≥ 2 and every topological group G, a simplicial space B * (q, G) is constructed where B n (q, G) = Hom(F n /Γ q , G) and the realizations B(q, G) = |B * (q, G)| filter the classifying space BG. In particular for q = 2 this yields a single space(More)
Atom interferometers covering macroscopic domains of space-time are a spectacular manifestation of the wave nature of matter. Because of their unique coherence properties, Bose-Einstein condensates are ideal sources for an atom interferometer in extended free fall. In this Letter we report on the realization of an asymmetric Mach-Zehnder interferometer(More)
Musts require nitrogen-containing compounds in order to ensure yeast development. This study examined the nitrogen-nutrient requirements of two commercial yeasts and three wild strains isolated from inoculated fermentations. The results showed that wild strains generally consumed lower amounts of amino acids than commercial yeasts. Most amino acids were(More)
Let Γ q denote the q-th stage of the descending central series of the free group on n generators F n. For each q ≥ 2 and every topological group G, a simplicial space B * (q, G) is constructed where B n (q, G) = Hom(F n /Γ q , G) and the realizations B(q, G) = |B * (q, G)| filter the classifying space BG. Homotopy properties of B(q, G) are considered for(More)
We realize beam splitters and mirrors for atom waves by employing a sequence of light pulses rather than individual ones. In this way we can tailor atom interferometers with improved sensitivity and accuracy. We demonstrate our method of composite pulses by creating a symmetric matter-wave interferometer which combines the advantages of conventional Bragg-(More)
A simple active control system is described that maintains the output of a single-mode fiber at prescribed polarization and intensity, thus counteracting erratic birefringeance effects in the fiber that are due to temperature drift and mechanical disturbances. Whereas the system of Ulrich [Appl. Phys. Lett. 35, 840 (1979)] controls two polarization(More)
We demonstrate a quantum gravimeter by combining the advantages of an atom chip for the generation, delta-kick collimation, and coherent manipulation of freely falling Bose-Einstein condensates (BECs) with an innovative launch mechanism based on Bloch oscillations and double Bragg diffraction. Our high-contrast BEC interferometer realizes tens of(More)