1,978 research outputs found
Characterization of a multimode coplanar waveguide parametric amplifier
We characterize a novel Josephson parametric amplifier based on a
flux-tunable quarter-wavelength resonator. The fundamental resonance frequency
is ~1GHz, but we use higher modes of the resonator for our measurements. An
on-chip tuning line allows for magnetic flux pumping of the amplifier. We
investigate and compare degenerate parametric amplification, involving a single
mode, and nondegenerate parametric amplification, using a pair of modes. We
show that we reach quantum-limited noise performance in both cases, and we show
that the added noise can be less than 0.5 added photons in the case of low
gain
Single-shot Readout of a Superconducting Qubit using a Josephson Parametric Oscillator
We propose and demonstrate a new read-out technique for a superconducting
qubit by dispersively coupling it to a Josephson parametric oscillator. We
employ a tunable quarter-wavelength superconducting resonator and modulate its
resonant frequency at twice its value with an amplitude surpassing the
threshold for parametric instability. We map the qubit states onto two distinct
states of classical parametric oscillation: one oscillating state, with
photons in the resonator, and one with zero oscillation amplitude.
This high contrast obviates a following quantum-limited amplifier. We
demonstrate proof-of-principle, single-shot readout performance, and present an
error budget indicating that this method can surpass the fidelity threshold
required for quantum computing.Comment: 11 pages, 5 figure
Removal of filler material from large high energy formed parts
Filler material is removed by applying steam heat at 88.99 C to underside of workpiece and allowing filler to melt and drain from the waffle grids
Solutocapillary Convection Effects on Polymeric Membrane Morphology
Macro voids are undesirable large pores in membranes used for purification. They form when membranes are cast as thin films on a smooth surface by evaporating solvent (acetone) from a polymer solution. There are two un-tested hypotheses explaining the growth of macro voids. One states that diffusion of the non-solvent (water) is solely responsible, while the other states that solutocapillary convection is the primary cause of macro void growth. Solutocapillary convection is flow-caused by a concentration induced surface-tension gradient. Macrovoid growth in the former hypothesis is gravity independent, while in the latter it is opposed by gravity. To distinguish between these two hypotheses, experiments were designed to cast membranes in zero-gravity. A semi-automated apparatus was designed and built for casting membranes during the 20 secs of zero-g time available in parabolic aircraft flight such as NASA's KC-135. The phase changes were monitored optically, and membrane morphology was evaluated by scanning electron microscopy (SEM). These studies appear to be the first quantitative studies of membrane casting in micro-gravity which incorporate real-time data acquisition. Morphological studies of membranes cast at 0, 1, and 1.8 g revealed the presence of numerous, sparse and no macrovoids respectively. These results are consistent with the predictions of the solutocapillary hypothesis of macrovoid growth
Fine structure and functional morphology of the mouthparts of a male Veigaia sp (Gamasida: Veigaiidae) with remarks on the spermatodactyl and related sensory structures
Mites of the genus Veigaia are common gamasid
inhabitants of forest litter. They engage in the
peculiar reproductive strategy of podospermy which, along
with other morphological and behavioral adaptations, involves
modification of the chelicerae of the relatively rare
males into gonopods. Each movable digit is provided with
an appendage (spermatodactyl) that is involved in sperm
transfer. We describe the gross anatomy, fine structure,
and functional morphology of the mouthparts of a male
Veigaia species and give ultrastructural details for the
corniculi, laciniae, preoral cavity, labrum, pharynx, and
movable and fixed digits. The fine structure of the spermatodactyl
is illustrated here for the first time in detail. A
semischematic reconstruction of the gnathosoma and
spermatodactyl is provided. The spermatodactyl is totally
fused with the movable digit and a sperm transfer duct
runs along its entire length. This duct starts at the adaxial
base of the movable digit, continues inside the digit into
the tube of the spermatodactyl, and finally opens at the
distal abaxial surface of the spermatodactyl. Several sensory
structures associated with the spermatodactyl probably
provide the male with mechanical and chemical
clues
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