2,538 research outputs found
Quantifying quantum discord and entanglement of formation via unified purifications
We propose a scheme to evaluate the amount of quantum discord and
entanglement of formation for mixed states, and reveal their ordering relation
via an intrinsic relationship between the two quantities distributed in
different partners of the associated purification. This approach enables us to
achieve analytical expressions of the two measures for a sort of quantum
states, such as an arbitrary two-qubit density matrix reduced from pure
three-qubit states and a class of rank-2 mixed states of 4\times 2 systems.
Moreover, we apply the scheme to characterize fully the dynamical behavior of
quantum correlations for the specified physical systems under decoherence.Comment: 4 pages, 2 figures, accepted for publication in Phys. Rev.
Exploring the linear space of Feynman integrals via generating functions
Deriving a comprehensive set of reduction rules for Feynman integrals has
been a longstanding challenge. In this paper, we present a proposed solution to
this problem utilizing generating functions of Feynman integrals. By
establishing and solving differential equations of these generating functions,
we are able to derive a system of reduction rules that effectively reduce any
associated Feynman integrals to their bases. We illustrate this method through
various examples and observe its potential value in numerous scenarios.Comment: 11 pages, 4 figures, references adde
Electrocardiogram Baseline Wander Suppression Based on the Combination of Morphological and Wavelet Transformation Based Filtering
One of the major noise components in electrocardiogram (ECG) is the baseline wander (BW). Effective methods for suppressing BW include the wavelet-based (WT) and the mathematical morphological filtering-based (MMF)algorithms. However, the T waveform distortions introduced by the WTand the rectangular/trapezoidal distortions introduced by MMF degrade the quality of the output signal. Hence, in this study, we introduce a method by combining the MMF and WTto overcome the shortcomings of both existing methods. To demonstrate the effectiveness of the proposed method, artificial ECG signals containing a clinicalBW are used for numerical simulation, and we also create a realistic model of baseline wander to compare the proposed method with
other state-of-the-art methods commonly used in the literature. /e results show that the BW suppression effect of the proposed method is better than that of the others. Also, the new method is capable of preserving the outline of the BW and avoiding waveform distortions caused by the morphology filter, thereby obtaining an enhanced quality of ECG
Top-Quark Decay at Next-to-Next-to-Next-to-Leading Order in QCD
We present the first complete high-precision QCD corrections to the inclusive
decay width , the -helicity fractions
and semi-inclusive distributions for the top-quark decay
process at NNNLO in the strong
coupling constant . In particular, the pure NNNLO QCD correction
decreases the by about of the previous NNLO result
at the top-quark pole mass scale, exceeding the error estimated by the usual
scale-variation prescription. After taking into account all sources of errors,
we get , the error of which meets the request by future
colliders. On the other hand, the NNNLO QCD effects on are
found to be much smaller, at the level of one per-mille for the dominating
, predestining them to act as precision observables for the top-quark
decay process.Comment: 7 pages, 3 figure
Latest data constraint of some parameterized dark energy models
Using various latest cosmological datasets including Type-Ia supernovae,
cosmic microwave background radiation, baryon acoustic oscillations, and
estimations of the Hubble parameter, we test some dark energy models with
parameterized equations of state and try to distinguish or select
observation-preferred models. We obtain the best fitting results of the six
models and calculate their values of the Akaike Information Criteria and Bayes
Information Criterion. And we can distinguish these dark energy models from
each other by using these two information criterions. However, the CDM model remains the best fit model. Furthermore, we perform geometric
diagnostics including statefinder and Om diagnostics to understand the
geometric behaviour of the dark energy models. We find that the six DE models
can be distinguished from each other and from CDM, Chaplygin gas,
quintessence models after the statefinder and Om diagnostics were performed.
Finally, we consider the growth factor of the dark energy models with
comparison to CDM model. Still, we find the models can be
distinguished from each other and from CDM model through the growth
factor approximation.Comment: 23 pages, 6 figures, to be published in CP
Heavy-quark pair production at lepton colliders at NNNLO in QCD
We compute the total cross-section and invariant mass distribution for
heavy-quark pair production in annihilation at the
next-to-next-to-next-to-leading order in QCD. The obtained results are
expressed as piecewise functions defined by several deeply expanded power
series, facilitating a rapid numerical evaluation. Utilizing top-pair
production at a collision energy of 500 GeV as a benchmark, we observe a
correction of approximately for the total cross-section and around
for the majority of the invariant mass distribution range. These results
play a crucial role in significantly reducing theoretical uncertainty: the
scale dependence has been diminished to for the total cross-section
and to for the invariant mass distribution. This reduction of uncertainty
meets the stringent requirements of future lepton colliders.Comment: 7 pages, 5 figures; invariant mass distribution for heavy-quark pair
added; version published at PR
SAMUS: Adapting Segment Anything Model for Clinically-Friendly and Generalizable Ultrasound Image Segmentation
Segment anything model (SAM), an eminent universal image segmentation model,
has recently gathered considerable attention within the domain of medical image
segmentation. Despite the remarkable performance of SAM on natural images, it
grapples with significant performance degradation and limited generalization
when confronted with medical images, particularly with those involving objects
of low contrast, faint boundaries, intricate shapes, and diminutive sizes. In
this paper, we propose SAMUS, a universal model tailored for ultrasound image
segmentation. In contrast to previous SAM-based universal models, SAMUS pursues
not only better generalization but also lower deployment cost, rendering it
more suitable for clinical applications. Specifically, based on SAM, a parallel
CNN branch is introduced to inject local features into the ViT encoder through
cross-branch attention for better medical image segmentation. Then, a position
adapter and a feature adapter are developed to adapt SAM from natural to
medical domains and from requiring large-size inputs (1024x1024) to small-size
inputs (256x256) for more clinical-friendly deployment. A comprehensive
ultrasound dataset, comprising about 30k images and 69k masks and covering six
object categories, is collected for verification. Extensive comparison
experiments demonstrate SAMUS's superiority against the state-of-the-art
task-specific models and universal foundation models under both task-specific
evaluation and generalization evaluation. Moreover, SAMUS is deployable on
entry-level GPUs, as it has been liberated from the constraints of long
sequence encoding. The code, data, and models will be released at
https://github.com/xianlin7/SAMUS
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