15,876 research outputs found
Charmless Decays in Factorization-Assisted Topological-Amplitude Approach
Within the factorization-assisted topological-amplitude approach, we studied
the 33 charmless decays, where stands for a light vector
meson. According to the flavor flows, the amplitude of each process can be
decomposed into 8 different topologies. In contrast to the conventional flavor
diagrammatic approach, we further factorize each topological amplitude into
decay constant, form factors and unknown universal parameters. By
fitting 46 experimental observables, we extracted 10 theoretical parameters
with per degree of freedom around 2. Using the fitted parameters, we
calculated the branching fractions, polarization fractions, CP asymmetries and
relative phases between polarization amplitudes of each decay mode. The decay
channels dominated by tree diagram have large branching fractions and large
longitudinal polarization fraction. The branching fractions and longitudinal
polarization fractions of color-suppressed decays become smaller. Current
experimental data of large transverse polarization fractions in the penguin
dominant decay channels can be explained by only one transverse amplitude of
penguin annihilation diagram. Our predictions of those not yet measured
channels can be tested in the ongoing LHCb experiment and the Belle-II
experiment in future.Comment: 22 pages, 2 figure
Experimental Test of Quantum Jarzynski Equality with a Trapped Ion System
The past two decades witnessed important developments in the field of
non-equilibrium statistical mechanics. Among these developments, the Jarzynski
equality, being a milestone following the landmark work of Clausius and Kelvin,
stands out. The Jarzynski equality relates the free energy difference between
two equilibrium states and the work done on the system through far from
equilibrium processes. While experimental tests of the equality have been
performed in classical regime, the verification of the quantum Jarzynski
equality has not yet been fully demonstrated due to experimental challenges.
Here, we report an experimental test of the quantum Jarzynski equality with a
single \Yb ion trapped in a harmonic potential. We perform projective
measurements to obtain phonon distributions of the initial thermal state.
Following that we apply the laser induced force on the projected energy
eigenstate, and find transition probabilities to final energy eigenstates after
the work is done. By varying the speed of applying the force from equilibrium
to far-from equilibrium regime, we verified the quantum Jarzynski equality in
an isolated system.Comment: 18 pages, 4 figures, 1 tabl
Phonon arithmetic in a trapped ion system
Single-quantum level operations are important tools to manipulate a quantum state. Annihilation or creation of single particles translates a quantum state to another by adding or subtracting a particle, depending on how many are already in the given state. The operations are probabilistic and the success rate has yet been low in their experimental realization. Here we experimentally demonstrate (near) deterministic addition and subtraction of a bosonic particle, in particular a phonon of ionic motion in a harmonic potential. We realize the operations by coupling phonons to an auxiliary two-level system and applying transitionless adiabatic passage. We show handy repetition of the operations on various initial states and demonstrate by the reconstruction of the density matrices that the operations preserve coherences. We observe the transformation of a classical state to a highly non-classical one and a Gaussian state to a non-Gaussian one by applying a sequence of operations deterministically
Learning mechanistic metabolic models with small datasets
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CIF-PT: Bridging Speech and Text Representations for Spoken Language Understanding via Continuous Integrate-and-Fire Pre-Training
Speech or text representation generated by pre-trained models contains
modal-specific information that could be combined for benefiting spoken
language understanding (SLU) tasks. In this work, we propose a novel
pre-training paradigm termed Continuous Integrate-and-Fire Pre-Training
(CIF-PT). It relies on a simple but effective frame-to-token alignment:
continuous integrate-and-fire (CIF) to bridge the representations between
speech and text. It jointly performs speech-to-text training and language model
distillation through CIF as the pre-training (PT). Evaluated on SLU benchmark
SLURP dataset, CIF-PT outperforms the state-of-the-art model by 1.94% of
accuracy and 2.71% of SLU-F1 on the tasks of intent classification and slot
filling, respectively. We also observe the cross-modal representation extracted
by CIF-PT obtains better performance than other neural interfaces for the tasks
of SLU, including the dominant speech representation learned from
self-supervised pre-training.Comment: Accepted by ACL 2023 Finding
Pharmacological Basis for Use of Armillaria mellea
Armillaria mellea, an edible fungus, exhibits various pharmacological activities, including antioxidant and antiapoptotic properties. However, the effects of A. mellea on Alzheimer’s disease (AD) have not been systemically reported. The present study aimed to explore the protective effects of mycelium polysaccharides (AMPS) obtained from A. mellea, especially AMPSc via 70% ethanol precipitation in a L-glutamic acid- (L-Glu-) induced HT22 cell apoptosis model and an AlCl3 plus D-galactose- (D-gal-) induced AD mouse model. AMPSc significantly enhanced cell viability, suppressed nuclear apoptosis, inhibited intracellular reactive oxygen species accumulation, prevented caspase-3 activation, and restored mitochondrial membrane potential (MMP). In AD mice, AMPSc enhanced horizontal movements in an autonomic activity test, improved endurance times in a rotarod test, and decreased escape latency time in a water maze test. Furthermore, AMPSc reduced the apoptosis rate, amyloid beta (Aβ) deposition, oxidative damage, and p-Tau aggregations in the AD mouse hippocampus. The central cholinergic system functions in AD mice improved after a 4-week course of AMPSc administration, as indicated by enhanced acetylcholine (Ach) and choline acetyltransferase (ChAT) concentrations, and reduced acetylcholine esterase (AchE) levels in serum and hypothalamus. Our findings provide experimental evidence suggesting A. mellea as a neuroprotective candidate for treating or preventing neurodegenerative diseases
Experimental realization of optimal asymmetric cloning and telecloning via partial teleportation
We report an experimental realization of both optimal asymmetric cloning and
telecloning of single photons by making use of partial teleportation of an
unknown state. In the experiment, we demonstrate that, conditioned on the
success of partial teleportation of single photons, not only the optimal
asymmetric cloning can be accomplished, but also one of two outputs can be
transfered to a distant location, realizing the telecloning. The experimental
results represent a novel way to achieve the quantum cloning and may have
potential applications in the context of quantum communication.Comment: 4 pages and 4 figure
Experimental Construction of Optical Multi-qubit Cluster States From Bell States
Cluster states serve as the central physical resource for the
measurement-based quantum computation. We here present a simple experimental
demonstration of the scalable cluster-state-construction scheme proposed by
Browne and Rudolph. In our experiment, three-photon cluster states are created
from two Bell states using linear optical devices. By observing a violation of
three-particle Mermin inequality of , we also
for the first time report a genuine three-photon entanglement. In addition, the
entanglement properties of the cluster states are examined under and
measurements on a qubit.Comment: 4 pages, 4 figures, submitte
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