24,528 research outputs found
Validation of a new flying quality criterion for the landing task
A strong correlation has been found to exist between flight path angle peak overshoot and pilot ratings for the landing task. The use of flightpath overshoot as a flying quality metric for landing is validated by correlation with four different in-flight simulation programs and a ground simulation study. Configurations tested were primarily medium-weight generic transports. As a result of good correlation with this extensive data base, criterion boundaries are proposed for landing based on the flight path peak overshoot metric
Equivalence between two-mode spin squeezed states and pure entangled states with equal spin
We prove that a pure entangled state of two subsystems with equal spin is
equivalent to a two-mode spin-squeezed state under local operations except for
a set of bipartite states with measure zero, and we provide a counterexample to
the generalization of this result to two subsystems of unequal spin.Comment: 6 pages, no figure
Berry Curvature on the Fermi Surface: Anomalous Hall Effect as a Topological Fermi-Liquid Property
The intrinsic anomalous Hall effect in metallic ferromagnets is shown to be
controlled by Berry phases accumulated by adiabatic motion of quasiparticles on
the Fermi surface, and is purely a Fermi-liquid property, not a ``bulk'' Fermi
sea property like Landau diamagnetism, as has been previously supposed. Berry
phases are a new topological ingredient that must be added to Landau
Fermi-liquid theory in the presence of broken inversion or time-reversal
symmetry.Comment: 4 pages, 0 figures; to appear in Physical Review Letters; cleaner
form of main formula+note added confirming continued validity of result in
interacting Fermi liquids: + improved summary paragraph stating result; final
published version (minor changes
A polyphonic acoustic vortex and its complementary chords
Using an annular phased array of eight loudspeakers, we generate sound beams that simultaneously contain phase singularities at a number of different frequencies. These frequencies correspond to different musical notes and the singularities can be set to overlap along the beam axis, creating a polyphonic acoustic vortex. Perturbing the drive amplitudes of the speakers means that the singularities no longer overlap, each note being nulled at a slightly different lateral position, where the volume of the other notes is now nonzero. The remaining notes form a tri-note chord. We contrast this acoustic phenomenon to the optical case where the perturbation of a white light vortex leads to a spectral spatial distribution
STUDIES ON ABLATION OF OBJECTS TRAVERSING AN ATMOSPHERE
Ablation-type thermal protection of objects traversing an atmosphere - earth and mar
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