Nature, April 7, 2022, Volume 604, No.7904.

Nature, April 7, 2022, Volume 604, No.7904.

Astronomy astronomy

Ultraviolet Absorption of Silicate Cloud Precursors in Superheated Jupiter WASP- 178b

Ultraviolet absorption of silicate cloud precursors in Jupiter-sized high-temperature planet WASP- 178b.

Authors: Joshua D. Lothringer, David K. Sing, Zafar Rustamkulov, Hannah R. Wakefud, Kevin B. Stevenson, Nikolay Nikolov, Panayotis Lavvas, Jessica J. Speke &; Autumn T. winch

Link:

/articles/s 4 1586-022-04453-2

abstract:

Here, we report the near-ultraviolet transmission spectrum of Jupiter-sized high-temperature planet WASP- 178b (about 2450 K), which shows a lot of absorption. Bayesian inversion shows that the existence of gaseous refractories containing silicon and magnesium is a precursor of condensation clouds at low temperature.

According to previous research, no SiO has been detected in exoplanets before, but the content of SiO in WASP- 178b is consistent with the theoretical expectation, that is, the main source of silicon at high temperature. These enable us to reinterpret the observation results that HAT-P-4 1b and WASP- 12 1b did not consider SiO, indicating that the formation of silicate clouds started from exoplanets with equilibrium temperatures between 1950 and 2450 K.

abstract:

Here, we report the near-ultraviolet transmission spectrum of super-hot Jupiter WASP- 178b (about 2450K), which shows remarkable absorption. Bayesian inversion shows that there are gaseous refractory substances containing silicon and magnesium, which are the precursors of condensation clouds at low temperature. Especially silicon monoxide, as far as we know, has not been detected in exoplanets before, but the existence of silicon monoxide in WASP- 178b is consistent with the theoretical expectation, and it is the main silicon-containing species at high temperature. These observations lead us to reinterpret the previous observations of HAT-P-4 1b and WASP- 12 1b, which do not consider SiO, indicating that the formation of silicate clouds started from exoplanets with equilibrium temperatures between 1 950 and 2,450.

Physics physics

Searching for Majorana Neutrinos by CUORE's Millikelvin Cryonics

Searching for majorana Neutrinos with Crystals in Extremely Low Temperature Environment

Author: CUORE Cooperation Organization

Link:

/articles/s 4 1586-022-04497-4

abstract

Here, we show the latest cryostat without neutrino double β decay in 130Te crystal and the search results of CUORE experiment. The working temperature of CUORE experiment is only higher than absolute zero 10 nm, which improves the technological frontier in three aspects: quality at ultra-low temperature, working life and low-level ionizing radiation generated by low-temperature infrastructure.

The results show that neutrino-free double β does not decay within 90% confidence interval, and its lower half-life is 2.2 1025. We discuss the potential application progress of CUORE in other fields, such as direct dark matter, neutrino and nuclear physics search, as well as large-scale quantum computation of large-scale payloads that benefit from continuous operation in low radioactivity and ultra-low temperature environment.

abstract

Here we show the research results of 0 ν β decay of 130Te by using the latest advanced low temperature calorimeter in CUORE experiment. CUORE operates at the temperature above absolute zero 10 millikelvin, which promotes the most advanced technology in three frontier fields: absolute quality maintained at such ultra-low temperature, operating life, and low-level ionizing radiation emitted by low-temperature infrastructure. We found no evidence of 0νββ decay, and the lower limit of the half-life of this process was 2.2 1025 years in a 90% confidence interval. We discuss the potential applications of CUORE's progress in other fields, such as direct dark matter, neutrino and nuclear physics search and large-scale quantum computing, which can benefit from the continuous operation of large payloads in low radioactivity and ultra-low temperature environment.

materials science

Electron nematic driven by charge density wave in kagome superconductor

Discovery of New Electron Nematic Phase in Cage Superconductors

Authors: Nie Linpeng, Sun Kuanlv, Wan Ruma, Dian, Zheng et al.

Link:

/articles/s 4 1586-022-04493-8

abstract

Through the combination of elastic resistance, nuclear magnetic resonance (NMR) and scanning tunneling microscopy/spectroscopy (STM/S), we found the evidence that there is an electron nematic phase in the cage superconductor CsV3Sb5. The elastic resistance coefficient (m 1 1-m 12) and NMR spectra show that the C2 structure of 202A0 supermonomer is distorted due to out-of-plane modulation, and there will be considerable nematic fluctuation below the charge density wave transition (about 94 Kelvin), and finally there will be nematic transition below 35 Kelvin.

The long-range nematic phase with fixed C2 structure below the transition temperature is realized by STM experiment, and a new nematic phase described by three-state Potts model is proposed.

abstract

Here, we report the evidence of electron nematic in CsV3Sb5 using the combination of elastic resistance measurement, nuclear magnetic resonance (NMR) and scanning tunneling microscope/spectroscopy (STM/S). The temperature-dependent elastic resistance coefficient (m 1 1 minus m 12) and NMR spectra show that besides the C2 structural distortion of the 2a0 2a0 supercell caused by out-of-plane modulation, a considerable nematic fluctuation occurs immediately under the CDW transition (about 94 Kelvin), and finally the nematic transition occurs under about 35 Kelvin. STM experiment directly shows the long-range nematic order of C2 structure pinned below nematic transition temperature, indicating a new nematic property described by three-state Potts model.

Ultrathin ferromagnetic hfo 2-z ro2–ZrO _ 2 superlattice gate stack for advanced transistors

Ultra-thin iron HFO _ 2-zirconia superlattice stack for advanced transistors

Authors: Surajie, Nima Anshanke, Li, Xu Chengxiang, etc.

Link:

/articles/s 4 1586-022-04425-6

abstract

Here, we report that the HFO 2-ZrO 2–ZrO _ 2 superlattice heterostructure is used as the gate stack, which is stabilized by the mixed ferroelectric-antiferroelectric sequence and directly integrated into the Si transistor, and is reduced to about 20 Angstroms, which is the same as the gate oxide thickness required for high-performance transistors. The total equivalent oxide layer thickness of the metal oxide semiconductor capacitor is equivalent to the effective thickness of silicon dioxide of 6.5 angstroms.

In the traditional HfO2 _ 2 _ 2-based high dielectric constant gate stack, if the silicon dioxide on the surface is not removed, such a low effective oxide layer thickness and the resulting large capacitance cannot be obtained, which has adverse effects on electron transmission and gate leakage current. Therefore, our gate stack can provide lower leakage current and will not reduce mobility without such cleaning.

abstract

Here, we report that the HFO 2–ZrO 2 superlattice heterostructure is used as the gate stack, which is stabilized in the mixed ferroelectric–antiferroelectric order, directly integrated into the Si transistor, and reduced to about 20? ngstr？ Ms, the same gate oxide thickness required for high performance transistors. The total equivalent oxide thickness in the metal-oxide-semiconductor capacitor S corresponds to the effective silicon dioxide thickness of about 6.5 angstroms. Without removing the interfacial silicon dioxide, such a low effective oxide thickness and large capacitance can not be achieved in the traditional high dielectric constant gate stack based on HfO2, and the interfacial silicon dioxide has adverse effects on electron transmission and gate leakage current. Therefore, our gate stack that does not require such cleaning provides relatively low leakage current without mobility degradation.

Biological biology

Stable hippocampus code of free-flying bats

Stable hippocampus coding of free-flying bats

Authors: William A. Liberty III, tobias A. schmid, Angelo Li, Madeleine Snyder &; Michael yartsev

Link:

/articles/s 4 1586-022-04560-0

abstract

Here, we use wireless calcium imaging technology to monitor the activity of CA 1 hippocampal neurons in the back of free-flying bats, which fly in familiar environments with high repeatability. We found that the participation and spatial selectivity of most neurons remained stable within a few days and weeks. We also found that the obvious change of tuning can be attributed to the change of bat flight behavior to a great extent.

Finally, we found that in the same environment, when bats fly under different room lighting conditions (turning on and off lights), their flight behavior has changed greatly, which may give people the illusion that neurons are unstable.

However, when comparing similar flight paths under different conditions, the stability of hippocampus coding persists. To sum up, we find that if behavior is taken into account, the potential hippocampal coding is highly stable within a few days and across environments.

abstract

Here, we use wireless calcium imaging to monitor the activity of CA 1 hippocampal neurons on the dorsal side of free-flying bats, which are flying in a highly reproducible environment. We found that the participation and spatial selectivity of most neurons remained stable within a few days or weeks. We also found that the obvious change of tuning can be attributed to the change of bat flight behavior to a great extent. Finally, we found that bats fly in the same environment under different indoor lighting conditions (turning on and turning off the lights), showing significant changes in flight behavior, which can give people an illusion of unstable neurons. However, when comparing similar flight paths under different conditions, the stability of hippocampus code still exists. To sum up, we show that if behavior is taken into account, the potential hippocampus coding is highly stable in a few days and in different environments.

neurosciences

Entropy of urban street network related to future spatial navigation ability

Entropy of urban street network related to future spatial navigation ability

Authors: A. Coutro, E. Manley, S. Goodroe, C. Gahnstrom, G. Filomena, D. Yesiltepe, R. C. Dalton, J. M. Wiener, C. HLScher, M.Hornberger &; Speer

Link:

/articles/s 4 1586-022-04486-7

abstract

Here, we use cognitive tasks embedded in video games to measure the navigation ability of 39,765,438+062 people from 38 countries around the world. Generally speaking, we find that people who grew up in non-urban areas are better at navigation. More specifically, people are better at navigating in environments whose topology is similar to that where they grew up.

People who grew up in cities with low street network entropy (such as Chicago) performed better in video games with regular layout, while those who grew up outside cities or in street networks with high entropy (such as Prague) performed better in video games with high entropy.

This provides evidence for the global influence of environment on human cognition and emphasizes the importance of urban design in human cognition and brain function.

abstract

Here, we use cognitive tasks embedded in video games to measure the nonverbal spatial navigation ability of 397, 162 people from 38 countries around the world. Generally speaking, we find that people who grew up outside the city are better at navigation. More specifically, people are better at navigating in environments with similar topologies to those where they grew up. Growing up in a city with low street network entropy (for example, Chicago) will get better results in the video game level with regular layout, while growing up outside the city or in a city with high street network entropy (for example, Prague) will get better results in the video game level with higher entropy. This provides evidence for the influence of environment on human cognition on a global scale, and emphasizes the importance of urban design in human cognition and brain function.