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71.
In this paper, we present a gauge inflation model based on the orbifold M_4×S~1/Z_2 with non-Abelian SU(2) gauge symmetry, which is probably the simplest model in this category. As the inflaton potential is fully radiatively generated exclusively by gauge self-interactions, the model is predictive; thus, it is protected by gauge symmetry itself, without the introduction of any additional matter fields or arbitrary interactions. We show that the model fully agrees with the recent cosmological observations within the controlled perturbative regime of gauge interactions, g4≤1/(2πRMP), with the compactification radius(10 ≤ RMP ≤ 100): the expected magnitude of the curvature perturbation power spectrum and the value of the corresponding spectral index are in perfect agreement with the recent observations. The model also predicts a large fraction of the gravitational waves, negligible nonGaussianity, and a sufficiently high reheating temperature. 相似文献
72.
New unification theories predict large extra dimensions (LEDs). If that is the case, gravity would be stronger at short ranges than what Newtonian gravity predicts. LEDs could also have effects at atomic level. In this paper we propose a new method to constrain the size of ‘gravity-only’ LEDs by analysing how these LEDs modify the energy of the atomic transitions 1s-2s and 2s-2p (Lamb shift), in the particular case of the hydrogen and muonium atoms. We estimate these effects by using Bethe's non-relativistic treatment of Lamb shift. In the particular case of three LEDs, which may be a candidate to explain the interaction mechanism of dark matter particles, we have found that current knowledge in atomic spectroscopy could constrain their sizes to less than 10 μm. Although our contributions do not reach the sensitivity given by SN1987a, they are still slightly better than recent constraints given by Inverse Square Law tests of the Eoet-Wash group at Washington University, which gave R3 〈 36.6 μm. 相似文献
73.
New unification theories predict large extra dimensions (LEDs). If
that is the case, gravity would be stronger at short ranges than what
Newtonian gravity predicts. LEDs could also have effects at atomic
level. In this paper we propose a new method to constrain the size of
`gravity-only' LEDs by analysing how these LEDs modify the energy of
the atomic transitions 1s--2s and 2s--2p (Lamb shift), in the
particular case of the hydrogen and muonium atoms. We estimate these
effects by using Bethe's non-relativistic treatment of Lamb shift. In
the particular case of three LEDs, which may be a candidate to
explain the interaction mechanism of dark matter particles, we have
found that current knowledge in atomic spectroscopy could constrain
their sizes to less than 10\,$\mu$m. Although our contributions do
not reach the sensitivity given by SN1987a, they are still slightly
better than recent constraints given by Inverse Square Law tests of
the E\"{o}t--Wash group at Washington University, which gave $R_{3}
< 36.6\,\mu$m. 相似文献
74.
A correct account of the collective motion of a cluster does not require the Lothe-Pound correction; furthermore, this correction is shown to contradict the laws of thermodynamics. 相似文献
75.
Keith Andrew Brett Bolen Chad A. Middleton 《General Relativity and Gravitation》2007,39(12):2061-2071
We examine the effect on cosmological evolution of adding a Gauss–Bonnet term to the standard Einstein–Hilbert action for
a (1 + 3) + d dimensional Friedman–Robertson–Walker (FRW) metric. By assuming that the additional dimensions compactify as a power law
as the usual 3 spatial dimensions expand, we solve the resulting dynamical equations and find that the solution may be of
either de Sitter or Kasner form depending upon whether the Gauss–Bonnet term or the Einstein term dominates. 相似文献
76.
采用差示扫描量热法(DSC)对进口特级初榨橄榄油中葵花籽油的掺假鉴别进行了系统研究。由橄榄油入手考察了升降温循环实验条件下油品的重复性及数据可靠性,以此为基础提出采用程序降温的方法研究油品的结晶特性。统计了研究体系内的8种特级初榨橄榄油、6种其他食用油以及5种比例的模拟掺假油的结晶峰温度值,建立了回归方程。结果表明:进口特级初榨橄榄油在-60~-46℃区间内具有尖锐的结晶峰;随着掺入葵花籽油比例的升高,模拟掺假油的结晶温度逐渐向低温区移动,结晶峰形由尖锐逐渐变平坦;由结晶起始温度和结晶峰值温度分别相对于掺假油体积分数建立的回归方程具有很好的相关性,可以快速准确地鉴别特级初榨橄榄油。 相似文献
77.
This review is a brief account on the application of a novel methodology to the quality control and authentication of extra-virgin olive oil. This methodology is based on the derivatization of the labile hydrogens of functional groups, such as hydroxyl and carboxyl groups, of olive oil constituents with the phosphorus reagent 2-chloro-4,4,5,5-tetramethyldioxaphospholane, and the use of the (31)P chemical shifts to identify the phosphitylated compounds. Various experimental aspects such as pertinent instrumentation, sample preparation, acquisition parameters and properties of the phosphorus reagent are reviewed. The strategy to assign the (31)P signals of the phosphitylated model compounds and olive oil constituents by employing 1D and 2D NMR experiments is presented. Finally, the capability of this technique to assess the quality and the genuineness of extra-virgin olive oil and to detect fraud is discussed. 相似文献
78.
In this paper we investigate the effects of the large extra dimensions on the two processes
e+e-→
H0Z0Z0 and e+e-→ H0Z0Z0 at linear colliders in both unpolarized and polarized collision modes. We
find that the virtual Kaluza-Klein graviton exchange can significantly enhance the cross section from their standard model expectations for these two processes. The results show that the
LED effect on the process
e+e-→
H0Z0Z0
allows the observation limits on
the effective scale MS to be probed up to 9.75 TeV and 10.1 TeV
in the unpolarized and
+-(λe+=1/2,
λe-=-1/2) polarized beam collision modes (with
Pe+=0.6,
Pe-=0.8), respectively. For the process
e+e-→
H0Z0Z0, these limits on MS can be
probed up to 6.06 TeV and 6.38 TeV in the unpolarized and polarized
collision modes separately. We find that the λe+=1/2,
λe-=-1/2 polarization collision mode in both
process e+e-→ H0Z0Z0 and e+e-→ H0Z0Z0
may provide a possibility to improve the
sensitivity in probing the LED effects. 相似文献
79.
Since there is an urgent need for novel treatments to combat the current coronavirus disease 2019 (COVID-19) pandemic, in silico molecular docking studies were implemented as an attempt to explore the ability of selected bioactive constituents of extra virgin olive oil (EVOO) to act as potent SARS-CoV-2 (severe acute respiratory syndrome coronavirus 2) antiviral compounds, aiming to explore their ability to interact with SARS-CoV-2 Spike key therapeutic target protein. Our results suggest that EVOO constituents display substantial capacity for binding and interfering with Spike (S) protein, both wild-type and mutant, via the receptor-binding domain (RBD) of Spike, or other binding targets such as angiotensin-converting enzyme 2 (ACE2) or the RBD-ACE2 protein complex, inhibiting the interaction of the virus with host cells. This in silico study provides useful insights for the understanding of the mechanism of action of the studied compounds at a molecular level. From the present study, it could be suggested that the studied active phytochemicals could potentially inhibit the Spike protein, contributing thus to the understanding of the role that they can play in future drug designing and the development of anti-COVID-19 therapeutics. 相似文献
80.
We propose a six-dimensional Universal Extra Dimensions (UED) model compactified on a real projective plane RP2, a two-sphere with its antipodal points being identified. We utilize the Randjbar-Daemi–Salam–Strathdee spontaneous sphere compactification with a monopole configuration of an extra UX(1) gauge field that leads to a spontaneous radius stabilization. Unlike the sphere and the S2/Z2 orbifold compactifications, the massless UX(1) gauge boson is safely projected out. We show how a compactification on a non-orientable manifold results in a chiral four-dimensional gauge theory by utilizing 6D chiral gauge and Yukawa interactions. The resultant Kaluza–Klein mass spectra are distinct from the ordinary UED models compactified on torus. We briefly comment on the anomaly cancellation and also on a possible dark matter candidate in our model. 相似文献