1,277 research outputs found
Generalized Rindler Wedge and Holographic Observer Concordance
We study the most general horizons of accelerating observers and find that in
a general spacetime, only spacelike surfaces satisfying a global condition
could become horizons of well-defined accelerating observers, which we name the
Rindler-convexity condition. The entanglement entropy associated with a
Rindler-convex region is proportional to the area of the enclosing surface.
This observer physics provides a novel perspective to define a well-defined
subregion in spacetime, named the generalized Rindler wedge, whose degrees of
freedom should be fully encoded within the subregion. We propose the
holographic interpretation of generalized Rindler wedges and provide evidence
from the observer correspondence, the subregion subalgebra duality, and the
equality of the entanglement entropy, respectively. We introduce time/space
cutoffs in the bulk to substantiate this proposition, generalize it, and
establish a holographic observer concordance framework, which asserts that the
partitioning of degrees of freedom through observation is holographically
concordant.Comment: v2: 41 pages, 9 figures; major expansion for the GRW spacetime
subregion duality and observer concordanc
Bayesian method for fitting the low-energy constants in chiral perturbation theory
The values of the low-energy constants (LECs) are very important in the
chiral perturbation theory. This paper adopts a Bayesian method with the
truncation errors to globally fit some next-leading order (NLO) LECs
and some next-to-next-leading order (NNLO) LECs . With the estimates of
the truncation errors, the fitting results of in the NLO and NNLO are
very close. The posterior distributions of indicate the
boundary-dependent relations of these . Ten are weakly dependent
on the boundaries and their values are reliable. The other are required
more experimental data to constrain their boundaries. Some linear combinations
of are also fitted with more reliable posterior distributions. If one
knows some more precise value of , some other can be obtained by
these values. With these fitting LECs, most observables provide a good
convergence, except for the scattering lengths and
. Two examples are also introduced to test the improvement of the
method. All the computations indicate that considering the truncation errors
can improve the global fit greatly, and more prior information can obtain
better fitting results. This fitting method can extend to the other effective
field theories and the perturbation theory.Comment: 35 pages, 8 figure
(E)-4-Chloro-N-(2,4,6-trimethylbenzylidene)aniline
In the title compound, C16H16ClN, the dihedral angle between the benzene rings is 24.61 (13)°. In the crystal, only van der Waals interactions occur between neighbouring molecules
Y Chromosomes of 40% Chinese Are Descendants of Three Neolithic Super-grandfathers
Demographic change of human populations is one of the central questions for
delving into the past of human beings. To identify major population expansions
related to male lineages, we sequenced 78 East Asian Y chromosomes at 3.9 Mbp
of the non-recombining region (NRY), discovered >4,000 new SNPs, and identified
many new clades. The relative divergence dates can be estimated much more
precisely using molecular clock. We found that all the Paleolithic divergences
were binary; however, three strong star-like Neolithic expansions at ~6 kya
(thousand years ago) (assuming a constant substitution rate of 1e-9/bp/year)
indicates that ~40% of modern Chinese are patrilineal descendants of only three
super-grandfathers at that time. This observation suggests that the main
patrilineal expansion in China occurred in the Neolithic Era and might be
related to the development of agriculture.Comment: 29 pages of article text including 1 article figure, 9 pages of SI
text, and 2 SI figures. 5 SI tables are in a separate ancillary fil
Strong Electronic Interaction of Amorphous Fe2O3 Nanosheets with Single‐Atom Pt toward Enhanced Carbon Monoxide Oxidation
Platinum‐based catalysts are critical to several chemical processes, but their efficiency is not satisfying enough in some cases, because only the surface active‐site atoms participate in the reaction. Henceforth, catalysts with single‐atom dispersions are highly desirable to maximize their mass efficiency, but fabricating these structures using a controllable method is still challenging. Most previous studies have focused on crystalline materials. However, amorphous materials may have enhanced performance due to their distorted and isotropic nature with numerous defects. Here reported is the facile synthesis of an atomically dispersed catalyst that consists of single Pt atoms and amorphous Fe2O3 nanosheets. Rational control can regulate the morphology from single atom clusters to sub‐nanoparticles. Density functional theory calculations show the synergistic effect resulted from the strong binding and stabilization of single Pt atoms with the strong metal‐support interaction between the in situ locally anchored Pt atoms and Fe2O3 lead to a weak CO adsorption. Moreover, the distorted amorphous Fe2O3 with O vacancies is beneficial for the activation of O2, which further facilitates CO oxidation on nearby Pt sites or interface sites between Pt and Fe2O3, resulting in the extremely high performance for CO oxidation of the atomic catalyst.An atomically Pt dispersed catalyst on amorphous Fe2O3 nanosheets is developed. The size effect of Pt and phase effect of support are explored. The synergistic effect results from the strong metal‐support interactions between the single Pt atoms and the amorphous Fe2O3 structure supports lead to an enhanced CO oxidation performance.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/151833/1/adfm201904278-sup-0001-S1.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/151833/2/adfm201904278.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/151833/3/adfm201904278_am.pd
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