21,116 research outputs found
Anomaly Inflow and Membranes in QCD Vacuum
We study the membrane-like structure of topological charge density and its
fluctuations in the QCD vacuum. Quark zero modes are localized on the membranes
and the resultant gauge anomaly is cancelled by the gauge variation of a
Chern-Simons type effective action in the bulk via the anomaly inflow
mechanism. The coupling between brane fluctuations, described by the rotations
of its normal vector, and the Chern-Simons current provides the needed anomaly
inflow to the membrane. This coupling is also related to the axial U(1) anomaly
which can induce brane punctures, and consequently quark-antiquark annihilation
across the brane. As the Chern-Simons current has a long-range character,
together with membranes it might lead to a solution to the confinement problem.Comment: 8 pages, no figure, Xth Conference on Quark Confinement and the
Hadron Spectru
Towards a Model of Understanding Social Search
Search engine researchers typically depict search as the solitary activity of
an individual searcher. In contrast, results from our critical-incident survey
of 150 users on Amazon's Mechanical Turk service suggest that social
interactions play an important role throughout the search process. Our main
contribution is that we have integrated models from previous work in
sensemaking and information seeking behavior to present a canonical social
model of user activities before, during, and after search, suggesting where in
the search process even implicitly shared information may be valuable to
individual searchers.Comment: Presented at 1st Intl Workshop on Collaborative Information Seeking,
2008 (arXiv:0908.0583
The effect of temperature evolution on the interior structure of HO-rich planets
For most planets in the range of radii from 1 to 4 R, water is a
major component of the interior composition. At high pressure HO can be
solid, but for larger planets, like Neptune, the temperature can be too high
for this. Mass and age play a role in determining the transition between solid
and fluid (and mixed) water-rich super-Earth. We use the latest high-pressure
and ultra-high-pressure phase diagrams of HO, and by comparing them
with the interior adiabats of various planet models, the temperature evolution
of the planet interior is shown, especially for the state of HO. It
turns out that the bulk of HO in a planet's interior may exist in
various states such as plasma, superionic, ionic, Ice VII, Ice X, etc.,
depending on the size, age and cooling rate of the planet. Different regions of
the mass-radius phase space are also identified to correspond to different
planet structures. In general, super-Earth-size planets (isolated or without
significant parent star irradiation effects) older than about 3 Gyr would be
mostly solid.Comment: Accepted by ApJ, in print for March 2014 (14 pages, 3 colored
figures, 1 table
Disguising quantum channels by mixing and channel distance trade-off
We consider the reverse problem to the distinguishability of two quantum
channels, which we call the disguising problem. Given two quantum channels, the
goal here is to make the two channels identical by mixing with some other
channels with minimal mixing probabilities. This quantifies how much one
channel can disguise as the other. In addition, the possibility to trade off
between the two mixing probabilities allows one channel to be more preserved
(less mixed) at the expense of the other. We derive lower- and upper-bounds of
the trade-off curve and apply them to a few example channels. Optimal trade-off
is obtained in one example. We relate the disguising problem and the
distinguishability problem by showing the the former can lower and upper bound
the diamond norm. We also show that the disguising problem gives an upper bound
on the key generation rate in quantum cryptography.Comment: 27 pages, 8 figures. Added new results for using the disguising
problem to lower and upper bound the diamond norm and to upper bound the key
generation rate in quantum cryptograph
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