2,812 research outputs found
System calibration method for Fourier ptychographic microscopy
Fourier ptychographic microscopy (FPM) is a recently proposed quantitative
phase imaging technique with high resolution and wide field-of-view (FOV). In
current FPM imaging platforms, systematic error sources come from the
aberrations, LED intensity fluctuation, parameter imperfections and noise,
which will severely corrupt the reconstruction results with artifacts. Although
these problems have been researched and some special methods have been proposed
respectively, there is no method to solve all of them. However, the systematic
error is a mixture of various sources in the real situation. It is difficult to
distinguish a kind of error source from another due to the similar artifacts.
To this end, we report a system calibration procedure, termed SC-FPM, based on
the simulated annealing (SA) algorithm, LED intensity correction and adaptive
step-size strategy, which involves the evaluation of an error matric at each
iteration step, followed by the re-estimation of accurate parameters. The great
performance has been achieved both in simulation and experiments. The reported
system calibration scheme improves the robustness of FPM and relaxes the
experiment conditions, which makes the FPM more pragmatic.Comment: 18 pages, 9 figure
A simple entanglement measure for multipartite pure states
A simple entanglement measure for multipartite pure states is formulated
based on the partial entropy of a series of reduced density matrices. Use of
the proposed new measure to distinguish disentangled, partially entangled, and
maximally entangled multipartite pure states is illustrated.Comment: 8 pages LaTe
A Maxwell-vector p-wave holographic superconductor in a particular background AdS black hole metric
We study the p-wave holographic superconductor for AdS black holes with
planar event horizon topology for a particular Lovelock gravity, in which the
action is characterized by a self-interacting scalar field nonminimally coupled
to the gravity theory which is labeled by an integer . As the Lovelock
theory of gravity is the most general metric theory of gravity based on the
fundamental assumptions of general relativity, it is a desirable theory to
describe the higher dimensional spacetime geometry. The present work is devoted
to studying the properties of the p-wave holographic superconductor by
including a Maxwell field which nonminimally couples to a complex vector field
in a higher dimensional background metric. In the probe limit, we find that the
critical temperature decreases with the increase of the index of the
background black hole metric, which shows that a larger makes it harder for
the condensation to form. We also observe that the index affects the
conductivity and the gap frequency of the holographic superconductors.Comment: 14 pages, 6 figure
Augmentations and immersed Lagrangian fillings
For a Legendrian link with or ,
immersed exact Lagrangian fillings L \subset \mbox{Symp}(J^1M) \cong
T^*(\mathbb{R}_{>0} \times M) of can be lifted to conical Legendrian
fillings of . When
is embedded, using the version of functoriality for Legendrian contact
homology (LCH) from [30], for each augmentation of the LCH algebra of , there is an induced
augmentation . With fixed, the set of homotopy classes of all such
induced augmentations, , is a
Legendrian isotopy invariant of . We establish methods to compute
based on the correspondence between Morse complex families and
augmentations. This includes developing a functoriality for the cellular DGA
from [31] with respect to Legendrian cobordisms, and proving its equivalence to
the functoriality for LCH. For arbitrary , we give examples of
Legendrian torus knots with distinct conical Legendrian fillings
distinguished by their induced augmentation sets.
We prove that when and every
-graded augmentation of can be induced in this manner by an
immersed Lagrangian filling. Alternatively, this is viewed as a computation of
cobordism classes for an appropriate notion of -graded augmented
Legendrian cobordism.Comment: 51 pages, 22 figures. Accepted version to appear in Journal of
Topology. Version 2 is shorter than Version 1 with more efficient exposition.
In places, readers desiring more details are referred to Version
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Mobile Internet Access Patterns for Travel: Comparison of Desktops, Tablets, and Phones
This study investigated information access patterns on desktops, tablets, and phones of a few different travel related websites through web log analysis. The results show that the three types of devices have different ratios of search traffic, referral traffic, and direct traffic. With a smaller screen on mobile devices, users visit fewer pages per visit, stay less time on the website per session, and have higher bounce rates. Content analysis revealed that travelers requested more specific information on mobile devices and general information on desktop computers, indicating information needs in late decision making stages on mobile devices
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