4,673 research outputs found
Spectral function and fidelity susceptibility in quantum critical phenomena
In this paper, we derive a simple equality that relates the spectral function
and the fidelity susceptibility , i.e. with being
the half-width of the resonance peak in the spectral function. Since the
spectral function can be measured in experiments by the neutron scattering or
the angle-resolved photoemission spectroscopy(ARPES) technique, our equality
makes the fidelity susceptibility directly measurable in experiments.
Physically, our equality reveals also that the resonance peak in the spectral
function actually denotes a quantum criticality-like point at which the solid
state seemly undergoes a significant change.Comment: 5 pages, 2 figure
What mechanisms dominate the activity of Geminid Parent (3200) Phaethon?
A long-term sublimation model to explain how Phaethon could provide the
Geminid stream is proposed. We find that it would take Myr or more for
Phaethon to lose all of its internal ice (if ever there was) in its present
orbit. Thus, if the asteroid moved from the region of a 5:2 or 8:3 mean motion
resonance with Jupiter to its present orbit less than Myr ago, it may have
retained much of its primordial ice. The dust mantle on the sublimating body
should have a thickness of at least m but the mantle could have been less
than m thick years ago. We find that the total gas production rate
could have been as large as then, and the gas flow could
have been capable of lifting dust particles of up to a few centimeters in size.
Therefore, gas production during the past millennium could have been sufficient
to blow away enough dust particles to explain the entire Geminid stream. For
present-day Phaethon, the gas production is comparatively weak. But strong
transient gas release with a rate of is
expected for its south polar region when Phaethon moves from to
mean anomaly near perihelion. Consequently, dust particles with radii
of can be blown away to form a dust tail. In addition, we find
that the large surface temperature variation of K near perihelion can
generate sufficiently large thermal stress to cause fracture of rocks or
boulders and provide an efficient mechanism to produce dust particles on the
surface. The time scale for this process should be several times longer than
the seasonal thermal cycle, thereby dominating the cycle of appearance of the
dust tail.Comment: 10 pages, 5 figures, Accepted for publication in Monthly Notices of
the Royal Astronomical Societ
Deep Saliency with Encoded Low level Distance Map and High Level Features
Recent advances in saliency detection have utilized deep learning to obtain
high level features to detect salient regions in a scene. These advances have
demonstrated superior results over previous works that utilize hand-crafted low
level features for saliency detection. In this paper, we demonstrate that
hand-crafted features can provide complementary information to enhance
performance of saliency detection that utilizes only high level features. Our
method utilizes both high level and low level features for saliency detection
under a unified deep learning framework. The high level features are extracted
using the VGG-net, and the low level features are compared with other parts of
an image to form a low level distance map. The low level distance map is then
encoded using a convolutional neural network(CNN) with multiple 1X1
convolutional and ReLU layers. We concatenate the encoded low level distance
map and the high level features, and connect them to a fully connected neural
network classifier to evaluate the saliency of a query region. Our experiments
show that our method can further improve the performance of state-of-the-art
deep learning-based saliency detection methods.Comment: Accepted by IEEE Conference on Computer Vision and Pattern
Recognition(CVPR) 2016. Project page:
https://github.com/gylee1103/SaliencyEL
Some new trajectory patterns and periodic behaviors of unstable second-order digital filter with two’s complement arithmetic
This letter shows some counter-intuitive simulation results that for some filter parameters in the extended boundaries of the stability triangle, the state vector will converge to a periodic orbit after some iterations, no matter what the initial conditions are. Also, a new pattern, which looks like a rotated letter ‘X’, is found. The center of the rotated letter is located at the origin and the slopes of the ‘straight lines’ of the rotated letter are equal to the values of the pole locations
Attribute-Guided Face Generation Using Conditional CycleGAN
We are interested in attribute-guided face generation: given a low-res face
input image, an attribute vector that can be extracted from a high-res image
(attribute image), our new method generates a high-res face image for the
low-res input that satisfies the given attributes. To address this problem, we
condition the CycleGAN and propose conditional CycleGAN, which is designed to
1) handle unpaired training data because the training low/high-res and high-res
attribute images may not necessarily align with each other, and to 2) allow
easy control of the appearance of the generated face via the input attributes.
We demonstrate impressive results on the attribute-guided conditional CycleGAN,
which can synthesize realistic face images with appearance easily controlled by
user-supplied attributes (e.g., gender, makeup, hair color, eyeglasses). Using
the attribute image as identity to produce the corresponding conditional vector
and by incorporating a face verification network, the attribute-guided network
becomes the identity-guided conditional CycleGAN which produces impressive and
interesting results on identity transfer. We demonstrate three applications on
identity-guided conditional CycleGAN: identity-preserving face superresolution,
face swapping, and frontal face generation, which consistently show the
advantage of our new method.Comment: ECCV 201
- …