581 research outputs found
Magnetic effects in heavy-ion collisions at intermediate energies
The time-evolution and space-distribution of internal electromagnetic fields
in heavy-ion reactions at beam energies between 200 and 2000 MeV/nucleon are
studied within an Isospin-dependent Boltzmann-Uhling-Uhlenbeck transport model
IBUU11. While the magnetic field can reach about G which is
significantly higher than the estimated surface magnetic field (
G) of magnetars, it has almost no effect on nucleon observables as the Lorentz
force is normally much weaker than the nuclear force. Very interestingly,
however, the magnetic field generated by the projectile-like (target-like)
spectator has a strong focusing/diverging effect on positive/negative pions at
forward (backward) rapidities. Consequently, the differential
ratio as a function of rapidity is significantly altered by the magnetic field
while the total multiplicities of both positive and negative pions remain about
the same. At beam energies above about 1 GeV/nucleon, while the integrated
ratio of total to multiplicities is not, the differential
ratio is sensitive to the density dependence of nuclear symmetry
energy . Our findings suggest that magnetic effects should
be carefully considered in future studies of using the differential
ratio as a probe of the at supra-saturation
densities.Comment: 12 pages including 8 figures and 1 tabl
Accuracy of Segment-Anything Model (SAM) in medical image segmentation tasks
The segment-anything model (SAM), was introduced as a fundamental model for
segmenting images. It was trained using over 1 billion masks from 11 million
natural images. The model can perform zero-shot segmentation of images by using
various prompts such as masks, boxes, and points. In this report, we explored
(1) the accuracy of SAM on 12 public medical image segmentation datasets which
cover various organs (brain, breast, chest, lung, skin, liver, bowel, pancreas,
and prostate), image modalities (2D X-ray, histology, endoscropy, and 3D MRI
and CT), and health conditions (normal, lesioned). (2) if the computer vision
foundational segmentation model SAM can provide promising research directions
for medical image segmentation. We found that SAM without re-training on
medical images does not perform as accurately as U-Net or other deep learning
models trained on medical images.Comment: Technical Repor
Ultrafast switchable spin-orbit coupling for silicon spin qubits via spin valves
Recent experimental breakthroughs, particularly for single-qubit and
two-qubit gates exceeding the error correction threshold, highlight silicon
spin qubits as leading candidates for fault-tolerant quantum computation. In
the existing architecture, intrinsic or synthetic spin-orbit coupling (SOC) is
critical in various aspects, including electrical control, addressability,
scalability, etc. However, the high-fidelity SWAP operation and quantum state
transfer (QST) between spin qubits, crucial for qubit-qubit connectivity,
require the switchable nature of SOC which is rarely considered. Here, we
propose a flexible architecture based on spin valves by electrically changing
its magnetization orientation within sub-nanoseconds to generate ultrafast
switchable SOC. Based on the switchable SOC architecture, both SWAP operation
of neighbor spin qubits and resonant QST between distant spins can be realized
with fidelity exceeding 99% while considering the realistic experimental
parameters. Benefiting from the compatible processes with the modern
semiconductor industry and experimental advances in spin valves and spin
qubits, our results pave the way for future construction of silicon-based
quantum chips.Comment: 22 pages, 5 figure
Quantum Coherence Effects in Four-level Diamond Atomic System
A symmetric four-level closed-loop type (the diamond
structure) atomic system driven by four coherent optical fields is
investigated. The system shows rich quantum interference and coherence
features. When symmetry of the system is broken, interesting phenomena such as
single and double dark resonances appear. As a result, the double
electromagnetically induced transparency effect is generated, which will
facilitate the implementation of quantum phase gate operation.Comment: 8pages, 19 figure
The impact of renal function on the prognostic value of N-terminal pro–B-type natriuretic peptide in patients with coronary artery disease
Background: The impact of renal function on the prognostic value of N-terminal pro–B-type natriureticpeptide (NT-proBNP) remains unclear in coronary artery disease (CAD). This study sought toinvestigate the value of using NT-proBNP level to predict prognoses of CAD patients with differentestimated glomerular filtration rates (eGFRs).Methods: A retrospective analysis was conducted from a single registered database. 2087 consecutivepatients with CAD confirmed by coronary angiography were enrolled. The primary endpoint was allcausemortality.Results: The mean follow-up time was 26.4 ± 11.9 months and death events occurred in 197 cases.The NT-proBNP levels increased with the deterioration of renal function, as well as the optimal cutoffvalues based on eGFR stratification to predict endpoint outcome (179.4 pg/mL, 1443.0 pg/mL,3478.0 pg/mL, for eGFR ≥ 90, 60–90 and < 60 mL/min/1.73 m2, respectively). Compared with theroutine cut-off value or overall optimal one, stratified optimal ones had superior predictive ability forendpoint in each eGFR group (all with the highest Youden’s J statistics). And the prognostic value becameweaker as eGFR level decreased (eGFR ≥ 90 vs. 60–90 vs. < 60 mL/min/1.73 m2, odds ratio [OR]7.7; 95% confidence interval [CI] 1.7–33.9 vs. OR 4.8; 95% CI 2.7–8.5 vs. OR 3.0; 95% CI 1.5–6.2).Conclusions: This study demonstrated that NT-proBNP exhibits different predictive values for prognosisfor CAD patients with different levels of renal function. Among the assessed values, the NT-proBNPcut-off value determined using renal function improve the accuracy of the prognosis prediction of CAD.Moreover, lower eGFR is associated with a higher NT-proBNP cut-off value for prognostic prediction
Probing two driven double quantum dots strongly coupled to a cavity
We experimentally and theoretically study a driven hybrid circuit quantum
electrodynamics (cQED) system beyond the dispersive coupling regime. Treating
the cavity as part of the driven system, we develop a theory applicable to such
strongly coupled and to multi-qubit systems. The fringes measured for a single
driven double quantum dot (DQD)-cavity setting and the enlarged splittings of
the hybrid Floquet states in the presence of a second DQD are well reproduced
with our model. This opens a path to study Floquet states of multi-qubit
systems with arbitrarily strong coupling and reveals a new perspective for
understanding strongly driven hybrid systems.Comment: 9 pages, 6 figure
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