1,107 research outputs found
Higgsphobic and fermiophobic Z' as a single dark matter candidate
A spin-1 Z' particle as a single dark matter candidate is investigated by
assuming that it does not directly couple to the Higgs boson and standard model
fermions and does not mix with the photon and Z boson. The remaining dominant
vertices are quartic Z'Z'ZZ and Z'Z'W+W-, which can induce effective
Z'Z'q\bar{q} couplings through standard-model gauge-boson loops. We discuss
constraints from the cosmological thermal relic density, and direct and
indirect-detection experiments, and find that a dark Z' can only exist above
the W boson mass threshold, and the effective quartic coupling of Z'Z'VV is
bounded in the region of 10^{-3}~10^{-2}.Comment: 18pages, 14 figure
Lecture Notes on Generalized Symmetries and Applications
In this lecture note, we give a basic introduction to the rapidly developing
concepts of generalized symmetries, from the perspectives of both high energy
physics and condensed matter physics. In particular, we emphasize on the
(invertible) higher-form and higher-group symmetries. For the physical
applications, we discuss the geometric engineering of QFTs in string theory and
the symmetry-protected topological (SPT) phases in condensed matter physics.
The lecture note is based on a short course on generalized symmetries,
jointly given by Yi-Nan Wang and Qing-Rui Wang in Feb. 2023, which took place
at School of Physics, Peking University
(https://indico.ihep.ac.cn/event/18796/).Comment: 70 pages, Invited contribution for the Special Issue "Symmetry and
Chaos in Quantum Mechanics" for Symmetry (Ed. Dr. Cheng Peng
Exothermic isospin-violating dark matter after SuperCDMS and CDEX
We show that exothermic isospin-violating dark matter (IVDM) can make the
results of the latest CDMS-Si experiment consistent with recent null
experiments, such as XENON10, XENON100, LUX, CDEX, and SuperCDMS, whereas for
the CoGeNT experiment, a strong tension still persists. For CDMS-Si, separate
exothermic dark matter or isospin-violating dark matter cannot fully ameliorate
the tensions among these experiments; the tension disappears only if exothermic
scattering is combined with an isospin-violating effect of f_n/f_p=-0.7. For
such exothermic IVDM to exist, at least a new vector gauge boson (dark photon
or dark Z') that connects SM quarks to Majorana-type DM particles is required.Comment: 12 pages, 6 figure
Origin of Interfacial Polar Order in Incipient Ferroelectrics
There are ample experimental evidences indicating that the ferroelastic domain walls of incipient ferroelectrics, such as SrTiO3 and CaTiO3, are polar. The emergence of such interfacial polar order at a domain wall is exciting and believed to arise from the coupling between a primary order parameter, such as a strain or an antiferrodistortive (AFD) order parameter, and polarization. There have been several mechanisms proposed to explain the emergence of interfacial polar order, including biquadratic coupling, AFD-antiferroelectric coupling, and flexoelectric coupling. Using CaTiO3 as an example, we demonstrate, using both asymptotic analytics and numerical calculation, that the flexoelectric coupling is likely the dominant mechanism leading to the interfacial polar order
Noise suppression of on-chip mechanical resonators by chaotic coherent feedback
We propose a method to decouple the nanomechanical resonator in
optomechanical systems from the environmental noise by introducing a chaotic
coherent feedback loop. We find that the chaotic controller in the feedback
loop can modulate the dynamics of the controlled optomechanical system and
induce a broadband response of the mechanical mode. This broadband response of
the mechanical mode will cut off the coupling between the mechanical mode and
the environment and thus suppress the environmental noise of the mechanical
modes. As an application, we use the protected optomechanical system to act as
a quantum memory. It's shown that the noise-decoupled optomechanical quantum
memory is efficient for storing information transferred from coherent or
squeezed light
Possible Way to Synthesize Superheavy Element Z=117
Within the framework of the dinuclear system model, the production of
superheavy element Z=117 in possible projectile-target combinations is analyzed
systematically. The calculated results show that the production cross sections
are strongly dependent on the reaction systems. Optimal combinations,
corresponding excitation energies and evaporation channels are proposed in this
letter, such as the isotopes ^{248,249}Bk in ^{48}Ca induced reactions in 3n
evaporation channels and the reactions ^{45}Sc+^{246,248}Cm in 3n and 4n
channels, and the system ^{51}V+^{244}Pu in 3n channel.Comment: 10 pages, 4 figures, 1 tabl
Comparative study on saponin fractions from Panax notoginseng inhibiting inflammation-induced endothelial adhesion molecule expression and monocyte adhesion
<p>Abstract</p> <p>Background</p> <p><it>Panax notoginseng </it>is commonly used for the treatment of cardiovascular diseases in China. The present study investigates the effects of three different saponin fractions (<it>ie </it>total saponins, PNS; protopanaxadiol-type saponin, PDS; and protopanaxatriol-type saponin, PTS) and two major individual ingredients (<it>ie </it>ginsenoside Rg<sub>1 </sub>and Rb<sub>1</sub>) from <it>P. notoginseng </it>on the endothelial inflammatory response <it>in vitro </it>and <it>in vivo</it>.</p> <p>Methods</p> <p>Recombinant human tumor necrosis factor-α (TNF-α) was added to the culture medium of human coronary artery endothelial cells (HCAECs) to induce an inflammatory response. A cell adhesion assay was used to determine the effect of the <it>P. notoginseng </it>saponin fractions on endothelial-monocyte interaction. The cell adhesion molecule (CAMs) expression, including ICAM-1 and VCAM-1, in the protein level on the surface of endothelial cells were measured by cellular ELISA. CAMs expression in mRNA level was also assayed by qRT-PCR in the HCAECs and the aorta of rat fed with high cholesterol diet (HCD). Western blotting was used to detect effect of the saponin fractions on CAMs protein expression in HCAECs. In addition, nuclear translocation of p65, a surrogate marker for NF-κB activation, was measured by immunostaining.</p> <p>Results</p> <p>Three saponin fractions and two individual ginsenosides exhibited the inhibitory effects on monocyte adhesion on TNF-α-activated HCAECs and expression of ICAM-1 and VCAM-1 at both mRNA and protein levels <it>in vitro</it>. The saponin fractions exhibited a similar trend of the inhibitory effects on the mRNA expression of CAMs in the aorta of HCD-fed rat <it>in vivo</it>. These inhibitory effect of saponin fractions maybe attribute partially to the suppression of the TNF-α-induced NF-κB activation.</p> <p>Conclusion</p> <p>Our data demonstrate that saponin fractions (<it>ie </it>PNS, PDS and PTS) and major individual ginsenosides (<it>ie </it>Rg<sub>1 </sub>and Rb<sub>1</sub>) have potential anti-atherogenic effects. Among the tested saponin fractions, PDS is the most potent saponin fraction against TNF-α-induced monocyte adhesion as well as the expression of adhesion molecules <it>in vitro </it>and <it>in vivo</it>.</p
Prompt Space Optimizing Few-shot Reasoning Success with Large Language Models
Prompt engineering is an essential technique for enhancing the abilities of
large language models (LLMs) by providing explicit and specific instructions.
It enables LLMs to excel in various tasks, such as arithmetic reasoning,
question answering, summarization, relation extraction, machine translation,
and sentiment analysis. Researchers have been actively exploring different
prompt engineering strategies, such as Chain of Thought (CoT), Zero-CoT, and
In-context learning. However, an unresolved problem arises from the fact that
current approaches lack a solid theoretical foundation for determining optimal
prompts. To address this issue in prompt engineering, we propose a new and
effective approach called Prompt Space. Our methodology utilizes text
embeddings to obtain basis vectors by matrix decomposition, and then constructs
a space for representing all prompts. Prompt Space significantly outperforms
state-of-the-art prompt paradigms on ten public reasoning benchmarks. Notably,
without the help of the CoT method and the prompt "Let's think step by step",
Prompt Space shows superior performance over the few-shot method. Overall, our
approach provides a robust and fundamental theoretical framework for selecting
simple and effective prompts. This advancement marks a significant step towards
improving prompt engineering for a wide variety of applications in LLMs.Comment: Natural language processing (NLP
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