8,540 research outputs found
Single query learning from abelian and non-abelian Hamming distance oracles
We study the problem of identifying an n-bit string using a single quantum
query to an oracle that computes the Hamming distance between the query and
hidden strings. The standard action of the oracle on a response register of
dimension r is by powers of the cycle (1...r), all of which, of course,
commute. We introduce a new model for the action of an oracle--by general
permutations in S_r--and explore how the success probability depends on r and
on the map from Hamming distances to permutations. In particular, we prove that
when r = 2, for even n the success probability is 1 with the right choice of
the map, while for odd n the success probability cannot be 1 for any choice.
Furthermore, for small odd n and r = 3, we demonstrate numerically that the
image of the optimal map generates a non-abelian group of permutations.Comment: 14 page
The geometry of quantum learning
Concept learning provides a natural framework in which to place the problems
solved by the quantum algorithms of Bernstein-Vazirani and Grover. By combining
the tools used in these algorithms--quantum fast transforms and amplitude
amplification--with a novel (in this context) tool--a solution method for
geometrical optimization problems--we derive a general technique for quantum
concept learning. We name this technique "Amplified Impatient Learning" and
apply it to construct quantum algorithms solving two new problems: BATTLESHIP
and MAJORITY, more efficiently than is possible classically.Comment: 20 pages, plain TeX with amssym.tex, related work at
http://www.math.uga.edu/~hunziker/ and http://math.ucsd.edu/~dmeyer
Capsaicin as a Tool for Repelling Southern Flying Squirrels from Red-cockaded Woodpecker Cavities
The southern flying squirrel (Glaucomys volans) is an important kleptoparasite of cavities excavated by the imperiled red-cockaded woodpecker (Dryobates borealis). Flying squirrel usurpation of cavities may affect woodpecker productivity, but current efforts to manage flying squirrels are costly and time consuming. We assessed whether capsaicin could deter flying squirrel use of woodpecker cavities on a site in southwest Georgia, USA. Twenty-nine cavity tree clusters received 4 treatments: capsaicin, water, air, and a control (no treatment). Only capsaicin both removed more flying squirrels from the cavity immediately after its application and decreased the probability of a flying squirrel occupying the cavity the next day. The data presented supports the potential of capsaicin to provide a more efficient way for dealing with this common kleptoparasite
The Infrared Imaging Spectrograph (IRIS) for TMT: Volume phase holographic grating performance testing and discussion
Maximizing the grating efficiency is a key goal for the first light
instrument IRIS (Infrared Imaging Spectrograph) currently being designed to
sample the diffraction limit of the TMT (Thirty Meter Telescope). Volume Phase
Holographic (VPH) gratings have been shown to offer extremely high efficiencies
that approach 100% for high line frequencies (i.e., 600 to 6000l/mm), which has
been applicable for astronomical optical spectrographs. However, VPH gratings
have been less exploited in the near-infrared, particularly for gratings that
have lower line frequencies. Given their potential to offer high throughputs
and low scattered light, VPH gratings are being explored for IRIS as a
potential dispersing element in the spectrograph. Our team has procured
near-infrared gratings from two separate vendors. We have two gratings with the
specifications needed for IRIS current design: 1.51-1.82{\mu}m (H-band) to
produce a spectral resolution of 4000 and 1.19- 1.37 {\mu}m (J-band) to produce
a spectral resolution of 8000. The center wavelengths for each grating are
1.629{\mu}m and 1.27{\mu}m, and the groove densities are 177l/mm and 440l/mm
for H-band R=4000 and J-band R=8000, respectively. We directly measure the
efficiencies in the lab and find that the peak efficiencies of these two types
of gratings are quite good with a peak efficiency of ~88% at the Bragg angle in
both TM and TE modes at H-band, and 90.23% in TM mode, 79.91% in TE mode at
J-band for the best vendor. We determine the drop in efficiency off the Bragg
angle, with a 20-23% decrease in efficiency at H-band when 2.5 degree deviation
from the Bragg angle, and 25%-28% decrease at J-band when 5{\deg} deviation
from the Bragg angle.Comment: Proceedings of the SPIE, 9147-33
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