555 research outputs found
Quantum resource studied from the perspective of quantum state superposition
Quantum resources,such as discord and entanglement, are crucial in quantum
information processing. In this paper, quantum resources are studied from the
aspect of quantum state superposition. We define the local superposition (LS)
as the superposition between basis of single part, and nonlocal superposition
(NLS) as the superposition between product basis of multiple parts. For quantum
resource with nonzero LS, quantum operation must be introduced to prepare it,
and for quantum resource with nonzero NLS, nonlocal quantum operation must be
introduced to prepare it. We prove that LS vanishes if and only if the state is
classical and NLS vanishes if and only if the state is separable. From this
superposition aspect, quantum resources are categorized as superpositions
existing in different parts. These results are helpful to study quantum
resources from a unified frame.Comment: 9 pages, 4 figure
Negative exponential behavior of image mutual information for pseudo-thermal light ghost imaging: Observation, modeling, and verification
When use the image mutual information to assess the quality of reconstructed
image in pseudo-thermal light ghost imaging, a negative exponential behavior
with respect to the measurement number is observed. Based on information theory
and a few simple and verifiable assumptions, semi-quantitative model of image
mutual information under varying measurement numbers is established. It is the
Gaussian characteristics of the bucket detector output probability distribution
that leads to this negative exponential behavior. Designed experiments verify
the model.Comment: 13 pages, 6 figure
Binary sampling ghost imaging: add random noise to fight quantization caused image quality decline
When the sampling data of ghost imaging is recorded with less bits, i.e.,
experiencing quantization, decline of image quality is observed. The less bits
used, the worse image one gets. Dithering, which adds suitable random noise to
the raw data before quantization, is proved to be capable of compensating image
quality decline effectively, even for the extreme binary sampling case. A brief
explanation and parameter optimization of dithering are given.Comment: 8 pages, 7 figure
STGIC: a graph and image convolution-based method for spatial transcriptomic clustering
Spatial transcriptomic (ST) clustering employs spatial and transcription
information to group spots spatially coherent and transcriptionally similar
together into the same spatial domain. Graph convolution network (GCN) and
graph attention network (GAT), fed with spatial coordinates derived adjacency
and transcription profile derived feature matrix are often used to solve the
problem. Our proposed method STGIC (spatial transcriptomic clustering with
graph and image convolution) utilizes an adaptive graph convolution (AGC) to
get high quality pseudo-labels and then resorts to dilated convolution
framework (DCF) for virtual image converted from gene expression information
and spatial coordinates of spots. The dilation rates and kernel sizes are set
appropriately and updating of weight values in the kernels is made to be
subject to the spatial distance from the position of corresponding elements to
kernel centers so that feature extraction of each spot is better guided by
spatial distance to neighbor spots. Self-supervision realized by KL-divergence,
spatial continuity loss and cross entropy calculated among spots with high
confidence pseudo-labels make up the training objective of DCF. STGIC attains
state-of-the-art (SOTA) clustering performance on the benchmark dataset of
human dorsolateral prefrontal cortex (DLPFC). Besides, it's capable of
depicting fine structures of other tissues from other species as well as
guiding the identification of marker genes. Also, STGIC is expandable to
Stereo-seq data with high spatial resolution.Comment: Major revision has been made to generate the current version as
follows: 1. Writing style has been thoroughly changed. 2. Four more datasets
have been added. 3. Contrastive learning has been removed since it doesn't
make significant difference to the performance. 4. Two more authors are adde
General Physical Properties of Gamma-Ray-emitting Radio Galaxies
We study the radio galaxies with known redshift detected by the Fermi
satellite after 10 years of data (4FGL-DR2). We use a one-zone leptonic model
to fit the quasi-simultaneous multiwavelength data of these radio galaxies and
study the distributions of the derived physical parameter as a function of
black hole mass and accretion disk luminosity. The main results are as follows.
(1) We find that the jet kinetic power of most radio galaxies can be explained
by the hybrid jet model based on ADAFs surrounding Kerr black holes. (2) After
excluding the redshift, there is a significant correlation between the
radiation jet power and the accretion disk luminosity, while the jet kinetic
power is weakly correlated with the accretion disk luminosity. (3) We also find
a significant correlation between inverse Compton luminosity and synchrotron
luminosity. The slope of the correlation for radio galaxies is consistent with
the synchrotron self-Compton (SSC) process. The result may suggest that the
high-energy component of radio galaxies is dominated by the SSC process.Comment: 9 pages,7 figures, accept for publication in ApJ
The jet formation mechanism of Gamma-ray Narrow-line Seyfert 1 Galaxies
Under the coronal magnetic field, we estimate the maximal jet power of the
Blandford-\Znajek (BZ) mechanism, Blandford-\Payne (BP) mechanism, and hybrid
model. The jet power of the BZ and Hybrid model mechanisms depends on the spin
of a black hole, while the jet power of the BP mechanism does not depend on the
spin of a black hole. At high black hole spin, the jet power of the hybrid
model is greater than that of the BZ and BP mechanisms. We find that the jet
power of almost all gamma-\ray narrow line Seyfert 1 galaxies (gamma-\NLS1s)
can be explained by the hybrid model. However, one source with jet power 0.1~\1
Eddington luminosity can not be explained by the hybrid model. We suggest that
the magnetic field dragged inward by the accretion disk with
magnetization-\driven outflows may accelerate the jets in this gamma-\NLS1.Comment: 9 pages,6 figures,accepted for publication in MNRA
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