19,093 research outputs found
Defending the Public Good and Traditional Society: Non-Scriptural Religious Objections to Same-Sex Marriage
Hypersonic flow of air past a circular cylinder with non-equilibrium oxygen dissociation including dissociation of the free stream
Hypersonic inviscid flow past a circular cylinder with nonequilibrium oxygen dissociation and dissociation of the free strea
Toward Spin Squeezing with Trapped Ions
Building robust instruments capable of making interferometric measurements
with precision beyond the standard quantum limit remains an important goal in
many metrology laboratories. We describe here the basic concepts underlying
spin squeezing experiments that allow one to surpass this limit. In priniciple
it is possible to reach the so-called Heisenberg limit, which constitutes an
improvement in precision by a factor , where is the number of
particles on which the measurement is carried out. In particular, we focus on
recent progress toward implementing spin squeezing with a cloud of beryllium
ions in a Penning ion trap, via the geometric phase gate used more commonly for
performing two-qubit entangling operations in quantum computing experiments.Comment: 18 pages, 9 figures, Contribution to Quantum Africa 2010 conference
proceeding
Sit-and-Wait Strategies in Dynamic Visual Search
The role of memory in visual search has lately become a controversial issue. Horowitz and Wolfe (1998) observed that performance in a visual search task was little affected by whether the stimuli were static or randomly relocated every 111 ms. Because a memory-based mechanism, such as inhibition of return, would be of no use in the dynamic condition, Horowitz and Wolfe concluded that memory is likewise not involved in the static condition. However, Horowitz and Wolfe could not effectively rule out the possibility that observers adopted a different strategy in the dynamic condition than in the static condition. That is, in the dynamic condition observers may have attended to a subregion of the display and waited for the target to appear there (sit-and-wait strategy). This hypothesis is supported by experimental data showing that performance in their dynamic condition does not differ from performance in another dynamic condition in which observers are forced to adopt a sit-and-wait strategy by being presented with a limited region of the display only
An experimental evaluation of the performance deficit of an aircraft engine starter turbine
An experimental investigation was made to determine the reasons for the low aerodynamic performance of a 13.5 centimeter tip diameter aircraft engine starter turbine. The investigation consisted of an evaluation of both the stator and the stage. An approximate ten percent improvement in turbine efficiency was obtained when the honeycomb shroud over the rotor blade tips was filled to obtain a solid shroud surface
- …