1,070 research outputs found
Preparing a mechanical oscillator in non-Gaussian quantum states
We propose a protocol for coherently transferring non-Gaussian quantum states
from optical field to a mechanical oscillator. The open quantum dynamics and
continuous-measurement process, which can not be treated by the
stochastic-master-equation formalism, are studied by a new path-integral-based
approach. We obtain an elegant relation between the quantum state of the
mechanical oscillator and that of the optical field, which is valid for general
linear quantum dynamics. We demonstrate the experimental feasibility of such
protocol by considering the cases of both large-scale gravitational-wave
detectors and small-scale cavity-assisted optomechanical devices.Comment: 4 pages, 3 figure
Nearly strain-free heteroepitaxial system for fundamental studies of pulsed laser deposition: EuTiO3 on SrTiO3
High quality epitaxial thin-films of EuTiO3 have been grown on the (001)
surface of SrTiO3 using pulsed laser deposition. In situ x-ray reflectivity
measurements reveal that the growth is two-dimensional and enable real-time
monitoring of the film thickness and roughness during growth. The film
thickness, surface mosaic, surface roughness, and strain were characterized in
detail using ex situ x-ray diffraction. The thicnkess and composition were
confirmed with Rutherford Backscattering. The EuTiO3 films grow
two-dimensionally, epitaxially, pseudomorphically, with no measurable in-plane
lattice mismatch.Comment: 7 pages, 6 figure
Universal upper limit on inflation energy scale from cosmic magnetic field
Recently observational lower bounds on the strength of cosmic magnetic fields
were reported, based on gamma-ray flux from distant blazars. If inflation is
responsible for the generation of such magnetic fields then the inflation
energy scale is bounded from above as rho_{inf}^{1/4} < 2.5 times 10^{-7}M_{Pl}
times (B_{obs}/10^{-15}G)^{-2} in a wide class of inflationary magnetogenesis
models, where B_{obs} is the observed strength of cosmic magnetic fields. The
tensor-to-scalar ratio is correspondingly constrained as r< 10^{-19} times
(B_{obs}/10^{-15}G)^{-8}. Therefore, if the reported strength B_{obs} \geq
10^{-15}G is confirmed and if any signatures of gravitational waves from
inflation are detected in the near future, then our result indicates some
tensions between inflationary magnetogenesis and observations.Comment: 12pages, v2: several discussions and references added, version
accepted for publication by JCA
Matrix product decomposition and classical simulation of quantum dynamics in the presence of a symmetry
We propose a refined matrix product state representation for many-body
quantum states that are invariant under SU(2) transformations, and indicate how
to extend the time-evolving block decimation (TEBD) algorithm in order to
simulate time evolution in an SU(2) invariant system. The resulting algorithm
is tested in a critical quantum spin chain and shown to be significantly more
efficient than the standard TEBD.Comment: 5 pages, 4 figure
Clinical and Experimental Applications of NIR-LED Photobiomodulation
This review presents current research on the use of far-red to near-infrared (NIR) light treatment in various in vitro and in vivo models. Low-intensity light therapy, commonly referred to as “photobiomodulation,” uses light in the far-red to near-infrared region of the spectrum (630–1000 nm) and modulates numerous cellular functions. Positive effects of NIR–light-emitting diode (LED) light treatment include acceleration of wound healing, improved recovery from ischemic injury of the heart, and attenuated degeneration of injured optic nerves by improving mitochondrial energy metabolism and production. Various in vitro and in vivo models of mitochondrial dysfunction were treated with a variety of wavelengths of NIR-LED light. These studies were performed to determine the effect of NIR-LED light treatment on physiologic and pathologic processes. NIRLED light treatment stimulates the photoacceptor cytochrome c oxidase, resulting in increased energy metabolism and production. NIR-LED light treatment accelerates wound healing in ischemic rat and murine diabetic wound healing models, attenuates the retinotoxic effects of methanol-derived formic acid in rat models, and attenuates the developmental toxicity of dioxin in chicken embryos. Furthermore, NIR-LED light treatment prevents the development of oral mucositis in pediatric bone marrow transplant patients. The experimental results demonstrate that NIR-LED light treatment stimulates mitochondrial oxidative metabolism in vitro, and accelerates cell and tissue repair in vivo. NIR-LED light represents a novel, noninvasive, therapeutic intervention for the treatment of numerous diseases linked to mitochondrial dysfunction
Generalization Error in Deep Learning
Deep learning models have lately shown great performance in various fields
such as computer vision, speech recognition, speech translation, and natural
language processing. However, alongside their state-of-the-art performance, it
is still generally unclear what is the source of their generalization ability.
Thus, an important question is what makes deep neural networks able to
generalize well from the training set to new data. In this article, we provide
an overview of the existing theory and bounds for the characterization of the
generalization error of deep neural networks, combining both classical and more
recent theoretical and empirical results
Merging Galaxies in the SDSS EDR
We present a new catalog of merging galaxies obtained through an automated
systematic search routine. The 1479 new pairs of merging galaxies were found in
approximately 462 sq deg of the Sloan Digital Sky Survey Early Data Release
(SDSS EDR; Stoughton et al. 2002) photometric data, and the pair catalog is
complete for galaxies in the magnitude range 16.0 <= g* <= 20.
The selection algorithm, implementing a variation on the original
Karachentsev (1972) criteria, proved to be very efficient and fast. Merging
galaxies were selected such that the inter-galaxy separations were less than
the sum of the component galaxies' radii.
We discuss the characteristics of the sample in terms of completeness, pair
separation, and the Holmberg effect. We also present an online atlas of images
for the SDSS EDR pairs obtained using the corrected frames from the SDSS EDR
database. The atlas images also include the relevant data for each pair member.
This catalog will be useful for conducting studies of the general
characteristics of merging galaxies, their environments, and their component
galaxies. The redshifts for a subset of the interacting and merging galaxies
and the distribution of angular sizes for these systems indicate the SDSS
provides a much deeper sample than almost any other wide-area catalog to date.Comment: 58 pages, which includes 15 figures and 6 tables. Figures 2, 8, 9,
10, 11, 13, and 14 are provided as JPEG files. For online atlas, see
http://home.fnal.gov/~sallam/MergePair/ . Accepted for publication in A
Lowest-lying Tetra-Quark Hadrons in Anisotropic Lattice QCD
We present a detailed study of lowest-lying hadrons in
quenched improved anisotropic lattice QCD. Using the and
diquark-antidiquark local and smeared operators, we attempt to isolate the
signal for and states in two flavour
QCD. In the chiral limit of light-quark mass region, the lowest scalar
state is found to have a mass, MeV, which is slightly
lower than the experimentally observed . The results from our
variational analysis do not indicate a signature of a tetraquark resonance in
I=1 and I=2 channels. After the chiral extrapolation the lowest
state is found to have a mass, MeV. We analysed the
static potential extracted form a tetraquark Wilson loop and illustrated
the behaviour of the state as a bound state, unbinding at some critical
diquark separation. From our analysis we conclude that scalar system
appears as a two-pion scattering state and that there is no spatially-localised
state in the light-quark mass region.Comment: 9 pages, 10 figure
Biogeographic diversification of Eranthis (Ranunculaceae) reflects the geological history of the three great Asian plateaus
The evolutionary history of organisms with poor dispersal abilities usually parallels geological events. Collisions of the Indian and Arabian plates with Eurasia greatly changed Asian topography and affected regional and global climates as well as biotic evolution. However, the geological evolution of Asia related to these two collisions remains debated. Here, we used Eranthis, an angiosperm genus with poor seed dispersal ability and a discontinuous distribution across Eurasia, to shed light on the orogenesis of the Qinghai-Tibetan, Iranian and Mongolian Plateaus. Our phylogenetic analyses show that Eranthis comprises four major geographical clades: east Qinghai-Tibetan Plateau clade (I-1), North Asian clade (I-2), west Qinghai-Tibetan Plateau clade (II-1) and Mediterranean clade (II-2). Our molecular dating and biogeographic analyses indicate that within Eranthis, four vicariance events correlate well with the two early uplifts of the Qinghai-Tibetan Plateau during the Late Eocene and the Oligocene-Miocene boundary and the two uplifts of the Iranian Plateau during the Middle and Late Miocene. The origin and divergence of the Mongolian Plateau taxa are related to the two uplifts of the Mongolian Plateau during the Middle and Late Miocene. Additionally, our results are in agreement with the hypothesis that the central part of Tibet only reached an altitude of less than 2.3 km at approximately 40 Ma. This study highlights that organismal evolution could be related to the formation of the three great Asian plateaus, hence contributing to the knowledge on the timing of the key tectonic events in Asia
SO(1,1) dark energy model and the universe transition
We suggest a scalar model of dark energy with the SO(1,1) symmetry. The model
may be reformulated in terms of a real scalar field and the scale factor
so that the Lagrangian may be decomposed as that of the real quintessence
model plus the negative coupling energy term of to . The existence of
the coupling term leads to a wider range of and overcomes the
problem of negative kinetic energy in the phantom universe model. We propose a
power-law expansion model of univese with time-dependent power, which can
describe the phantom universe and the universe transition from ordinary
acceleration to super acceleration.Comment: 12 pages. submitted to CQ
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