"Science" (published 20220916) One week's paper guide

Compilation | Weiyi

Science, 16 SEPTEMBER 2022, VOL 377, Issue 6612

"Science" September 16, 2022, Vol. 377, Issue 6612

not

not

Astronomy Astronomy

not

not

not

not

not

not

Loss of a Satellite Could Explain Saturn ’s Obliquity and Young Rings

Overseas satellite destruction may explain the inclination of Saturn and the young planet ring

Author: Jack Wisdom, ROLA DBOUK, Burkhard Militzer, William B. Hubbard, Fraancis Nimmo, Brynna G. DOWNEY, ET AL.

Link:

https://www.science.org/doi/10.1126/sclence.abn1234

Summary:

The origin of about 26.7 ° Saturn and the origin of the Saturn's ring about 100 million years ago is still unknown. People have observed that Saturn's largest satellite Satellite Tuwei Six quickly moves outward, and may increase the inclination of Saturn through the resonance of the self -spin track with Neptune.

The research team used the data from Cassini to accurately estimate the rotation inertia of Saturn and found that it just exceeded the range required for resonance. They believe that Saturn had another satellite before and named it "蛹", which led to the increase in the angle of Saturn through Neptune.

About 100 million years ago, the instability of the "pupae" track could explain that the system was close to resonance, and formed a Saturn ring through tide tear with Saturn.

Abstract:

The origin of Saturn's ~26.7° obliquity and ~100-million-year-old rings is unknown. The observed rapid outward migration of Saturn's largest satellite, Titan, could have raised Saturn's obliquity through a spin-orbit precession resonance with Neptune. We use Cassini data to refine estimates of Saturn's moment of inertia, finding that it is just outside the range required for the resonance. We propose that Saturn previously had an additional satellite, which we name Chrysalis, that caused Saturn's obliquity to increase through the Neptune resonance. DestAbilization of Chrysalis's Orbit ~ 100 Million Years AGO Can THEN Explain the Proximity of the System to the Resonance and the Formation of the Rings Through A Gra construction encture

not

not

not

not

not

not

Physics Physics

not

not

not

not

not

not

Few-complete vacuum squeeezing in nanophotonics

Small cycle vacuum compression in nano -photonology

Author: Rajveer Nehra, Ryoto Sekine, Luis Ledezma, Qiushi Guo, Robert M. Gray, Arkadev Roy, et al.

Link:

https://www.science.org/doi/10.1126/sclence.abo6213

Summary:

One of the most basic quantum states of light is to compress the vacuum, one of which is less than the standard quantum noise limit. In nano -optical scholarship, it is still challenging to produce, manipulate and measure the quantum state with extensive scalable quantum information systems.

The research team reported on the development of lithium -based nano -photon platforms to demonstrate the production of compressed state on the same chip and full optical measurement. The compressed state spans the bandwidth of more than 25 Tai Hertz, which only supports a few light cycles. The measured 4.9 decibel compression exceeds the requirements of the extensive quantum information system, showing a practical path for scalable ultra -fast quantum nano -learning.

Abstract:

One of the most fundamental quantum states of light is the squeezed vacuum, in which noise in one of the quadratures is less than the standard quantum noise limit. In nanophotonics, it remains challenging to generate, manipulate, and measure such a quantum state with the performance required for a wide range of scalable quantum information systems. Here, we report the development of a lithium niobate–based nanophotonic platform to demonstrate the generation and all-optical measurement of squeezed states on the same chip. The generated squeezed states span more than 25 terahertz of bandwidth supporting just a few optical cycles. The measured 4.9 decibels of squeezing surpass the requirements for a wide range of quantum information systems, demonstrating a practical path toward scalable ultrafast quantum nanophotonics.

not

not

not

not

not

not

not

not

Direct Geometric Probe of Singularities in Band Structure

Direct geometric detection with strange points in the structure

Author: Charles d. Brown, Shao-Wen Chang, Malte N. Schwarz, TSZ-HIM Leung, Vladyslav Kozii, Alexander Avdoshkin, et al.

Link:

https://www.science.org/doi/10.1126/sclence.abm6442

Summary:

The energy landscape of a quantum system may have multiple energy -degraded energy surfaces, and shows the strange geometric structure of the wave function flow, which has a significant impact on the nature of the system. The ultra -cold atoms in optical lattles can indirectly express these points in the structure.

The research group measured the non -Abel transformation generated directly through the odd point. They accelerated the atom along a quasi -volume trajectory, the atom entered and turned, and then left the linear and the strange point of the recreation point of the hive lattice. The transmitted measurement determines that the number of topology windings of these strange points is 1 and 2, respectively.

The work introduces a unique method of detecting strange points, which helps to study the non -Dirak strange point in the ultra -cold atomic quantum simulator.

Abstract:

A quantum system's energy landscape may have points where multiple energy surfaces are degenerate and that exhibit singular geometry of the wave function manifold, with major consequences for the system's properties. Ultracold atoms in optical lattices have been used to indirectly characterize such points in the band structure . We measured the non-Abelian transformation produced by transport directly through the singularities. We accelerated atoms along a quasi-momentum trajectory that enters, turns, and then exits the singularities at linear and quadratic band-touching points of a honeycomb lattice. Measurements after transport identified the topological winding numbers of these singularities to be 1 and 2, respectively. Our work introduces a distinct method for probing singularities that enables the study of non-Dirac singularities in ultracold-atom quantum simulators.

not

not

not

not

not

not

not

Chemical Chemistry

not

not

not

not

not

not

Halogen-AND Group Transfer Reaction Enabled by Hydrogen Tunneling

Handalogenic atoms and group transfer reactions caused by hydrogen tunnel penetration

Author: Timothée Constantin, Bartosz Górski, Michael J. Tilby, Saloua Chelli, Fabio Juliá, Josep Llaveria, et al.

Link:

https://www.science.org/doi/10.1126/sclence.abq8663

Summary:

The carbon free radicals are used to generate carbon free radicals by halogen atoms and group transfer reactions. Tin and silicon test agents are used to maximize the interaction between the effects of 焓 (thermodynamics) and polar (dynamics) effects.

In this work, the research group showed the unique response mode of the quantum mechanical tunnel through the use of cycloidenne derivatives under mild photochemical conditions. This scheme activates alkyl and aromatically l -cyl halide, as well as several alcohol and sulfenol derivatives.

Experimental and computing studies revealed a atypical way, that is, the cycloonenne -based liberal radicals collaborate and extraction of halogen atom or group group through the reactivity of effective H atoms. This activation mechanism seems to be difficult to achieve in thermodynamics and dynamics, but it is feasible through quantum tunnels.

Abstract:

The generation of carbon radicals by halogen-atom and group transfer reactions is generally achieved using tin and silicon reagents that maximize the interplay of enthalpic (thermodynamic) and polar (kinetic) effects. In this work, we demonstrate a distinct reactivity mode enabled by quantum mechanical tunneling that uses the cyclohexadiene derivative γ-terpinene as the abstractor under mild photochemical conditions. This protocol activates alkyl and aryl halides as well as several alcohol and thiol derivatives. Experimental and computational studies unveiled a noncanonical pathway whereby a cyclohexadienyl radical undergoes concerted aromatization and halogen-atom or group abstraction through the reactivity of an effective H atom. This activation mechanism is seemingly thermodynamically and kinetically unfavorable but is rendered feasible through quantum tunneling.

not

not

not

not

not

not

Earth Science Earth Science

not

not

not

not

not

The Bengal Water Machine: Quantify Freshwater Capture in Bangladesh

Bangladesh water machine: quantitative freshwater collection in Bangladesh

Author: Mohammad ShamSudduha, Richard G. Taylor, MD Izazul haq, Sara Nowreen, Anwar Zahid and Kazi Matin Uddin Ahmed.

Link:

https://www.science.org/doi/10.1126/science.abm4730

not

Summary:

Global food security depends on the sustainability of irrigation agriculture. The seasons of seasonal humid seductive plains in Asian tropical areas have continued to increase, so that rice can also be planted in the dry season. This kind of groundwater pumping increases the use of groundwater storage, because under favorable conditions, the subsequent monsoon will increase the groundwater supplement.

The research team experienced a natural season -based seasonal freshwater storage collection solution. It was called "Bangladesh Watercraft", which revealed its potential and limitations.

According to 1 million pressure testing observations from 465 monitoring wells, the research group showed that from 1988 to 2018, the cumulative freshwater collection volume (75 to 90 cubic kilometers) caused by about 16 million small farmers' collective operations from 1988 to 2018 was equivalent Twice the capacity of the dam reservoir.

not

Abstract:

Global food security depends on the sustainability of irrigated agriculture. Rising groundwater withdrawals from seasonally humid, alluvial plains across tropical Asia have enabled dry-season rice cultivation. This groundwater pumpage increases available subsurface storage that under favorable conditions amplifies groundwater replenishment during the subsequent monsoon. We empirically quantified this nature-based solution to seasonal freshwater storage capture described as the “Bengal Water Machine,” revealing its potential and limitations. On the basis of a million piezometric observations from 465 monitoring wells, we show that the collective operation of ~16 million smallholder farmers in the Bengal Basin of Bangladesh from 1988 to 2018 has induced cumulative freshwater capture that volumetrically (75 to 90 cubic kilometers) is equivalent to twice the reservoir capacity of the Three Gorges Dam.

not

not

not

Sociology Sociology

not

not

not

not

not

not

A CAUSAL TEST of the Stringth of Weak Ties

Cause and effect test with weak connection strength

Author: Karthik Rajkumar, Guillaume Saint-Jacques, Iavor Bojinov, Erik Brynjolfsson and Sinan Ara.

Link:

https://www.science.org/doi/10.1126/sclence.abl4476

Summary:

The research team analyzed many large -scale random experimental data of LinkedIn "the person you know" (the algorithm recommended to the member of LinkedIn) to test how big the weak connection is in the world's largest professional social network in the world in the world's largest professional social network. To increase work liquidity.

In 5 years, experiments randomly changed the general degree of weak connection among more than 20 million people's networks, and during this period, it created 2 billion new contacts and 600,000 new tasks. The research results provide evidence of experimental causality that supports weak connection intensity, and it is recommended that three corrections of theory.

First of all, the strength of weak connection is non -linear. Statistical analysis found that there is a U -shaped relationship between the intensity and work transfer, and the weaker connection increases the work transfer, but to a certain extent, the marginal income of the weak connection has decreased. Secondly, the weak connection measured by interactive strength and the number of interconnected quantities shows different effects. The medium weak connection (measurement by interconnection) and the weakest connection (measured by interactive intensity) created the most work liquidity.

Third, the strength of weak connections varies from the industry. The weak connection increases the work liquidity of the high -tech industry, while the Qianglian Department increases the work liquidity of the low technology industry.

Abstract:

The authors analyzed data from multiple large-scale randomized experiments on LinkedIn's People You May Know algorithm, which recommends new connections to LinkedIn members, to test the extent to which weak ties increased job mobility in the world's largest professional social network. The experiments randomly varied the prevalence of weak ties in the networks of over 20 million people over a 5-year period, during which 2 billion new ties and 600,000 new jobs were created. The results provided experimental causal evidence supporting the strength of weak ties and suggested three revisions to the theory. First, the strength of weak ties was nonlinear. Statistical analysis found an inverted U-shaped relationship between tie strength and job transmission such that weaker ties increased job transmission but only to a point, after which there were diminishing marginal returns to tie Weakness. Second, Weak Ties Measured by Intensity and the Number of Mutual ConnePlayed V arying effects. Moderately weak ties (measured by mutual connections) and the weakest ties (measured by interaction intensity) created the most job mobility. Third, the strength of weak ties varied by industry. Whereas weak ties increased job mobility in more digital industries, Strong Ties Increased Job Mobility in Less Digital Industries.

not

not

not

not

not

Edit ｜ Fangyuan

Capture | Zhihai

= PNG "Data-NickName =" Science Network "Data-Alias =" ScienceNet-Cas "Data-Signature =" In-circle major events, industry insights, occasionally gossip ... produced by the world's largest Chinese science community, Chinese Science News Agency.We: [email protected]; submitting [email protected]. "Data-from =" 0 "data-is_biz_ban =" 0 " /> Cooperation matters: [email protected]

Submission: [email protected]

Like this article?Praise + watch support!

- END -