China Science & Technology Forum

[JSCh]

Biological Consequences of Climate Change on Epidemics May Be Scale-dependent
Nov 07, 2017

Conventional thinking holds that current climate warming will increase the prevalence and transmission of disease.

However, a recent study led by Prof. ZHANG Zhibin of the Chinese Academy of Sciences and Prof. Nils Christian Stenseth of the University of Oslo in Norway show that the impact of climate change on the prevalence of epidemics may be scale-dependent.

The study was conducted using two millennia of historical data from ancient China extracted from A Compendium of Chinese Meteorological Records of the Last 3,000 Years.

When data covering a large time scale were analyzed, the researchers found that climate cooling caused more epidemics. However, when data covering a small time scale were analyzed, the association between epidemics and temperature was not consistent; in other words, both positive and negative associations were observed.

Further analysis revealed that a long-term cool and dry climate trend contributed to more epidemics mainly via an increase in locusts and famines. Both long-term and short-term trends in epidemics were closely and positively associated with drought, flood, locust and famine events.

Conventional theory suggests that climate warming should cause more disease by increasing the rates of development, reproduction and/or survival of hosts and/or vectors directly. Evidence supporting this theory is mainly derived from analyses of short-term data.

On a large time scale, however, temperature not only affects hosts and vectors directly, but also indirectly by influencing precipitation, and then agricultural production, famine and finally disease.

The researchers found that long-term climate cooling trends caused more droughts in China, probably due to the weakening monsoon. Droughts caused more locusts and the collapse of agriculture, producing more famines. Hungry people were more susceptible to disease and infections due to weakened immunity.

The long-term effects of climate change were not easily captured by using short-term data. China has a long history of recording significant biological, climatic and social events, which provides a unique opportunity to study the biological consequences of long-term climate change.

This study highlights the scale-dependent effects of climate change on biological as well as natural disasters. In contrast with the conventional view, the researchers found that the biological consequences of climate could be nonmonotonic, i.e., the effects could be either positive or negative.

The study’s findings may have implications for human disease prevention. In the short term, more droughts, floods or a warm climate would increase the risk of disease prevalence. However, over the long term, climate cooling would cause more epidemics as well as other disasters.

The researchers expressed an urgent need to study the scale-dependent effects of climate change on human epidemics.

Frequency-dependent effects of biological and climatic factors on prevalence of human epidemics in ancient China (Image by IOZ)



Biological Consequences of Climate Change on Epidemics May Be Scale-dependent---Chinese Academy of Sciences

 

[JSCh]

Chinese researchers uncover genetic secrets behind aging rate
Source: Xinhua| 2017-11-09 03:06:52|Editor: yan



LONDON, Nov. 8 (Xinhua) -- A research team from China has discovered a genetic mechanism that affects animal's aging rate, shedding light on the biological basis and regulation of healthy aging, according to a study published Wednesday in the journal Nature.

Learning more about this process is important because the world's population is aging rapidly, and aging is also a major risk factor for diseases including neurodegenerative disorders and cancer.

To better understand the issue, a team led by Dr. Shi-Qing Cai at the Chinese Academy of Sciences analyzed the genetic origin of variability in the rate of aging by using Caenorhabditis elegans (C. elegans) as an animal model. C. elegans is a tiny free-living nematode with a length of about one millimeter, and it has been widely used in aging research.

In their short lifespan, C. elegans from different parts of the world showed distinct rates of declines in virility, feeding behavior, and locomotion during aging, according to the study.

Further analysis showed that genetic variations in a novel neuropeptide coding gene, rgba-1, and its receptor gene, npr-28, regulated aging rate of worm behaviors among the C. elegans.

The team believes that their study reveals the first genetic pathway underlying natural variation in the rate of aging, and uncovers an important role of neuropeptide-mediated glia-neuron signaling in controlling aging rate.

The pathway appears to affect C. elegans' virility and feeding behavior, but not its locomotion, suggesting that "the mechanism regulating declines of various behaviors might be quite different", said the first author of the study, Dr. Jiang-An Yin, who is a member of Cai's team.

It remains an important challenge to determine whether neuropeptides play a similar role in regulating human healthspan.

But this study provides new insights into the evolution of aging, suggesting that aging rates may have been affected by emergence of new genes, natural selection, and the interaction between different genetic loci.

"The genes underlying variation in aging rate among individuals have undergone long-term natural selection, and they usually do not affect animal growth and reproduction. Thus, these genes potentially can be good drug targets for future anti-aging treatments," said Yin.

Jiang-An Yin, Ge Gao, Xi-Juan Liu, Zi-Qian Hao, Kai Li, Xin-Lei Kang, Hong Li, Yuan-Hong Shan, Wen-Li Hu, Hai-Peng Li & Shi-Qing Cai. Genetic variation in glia–neuron signalling modulates ageing rate. Nature (2017). DOI: 10.1038/nature24463​

 

[JSCh]

A Joint Beam Commissioning Performed at CSNS
Nov 04, 2017

The joint beam commissioning among accelerators, target station and instruments started in the China Spallation Neutron Source (CSNS) on November 1, 2017.

At about 15:00 p.m., the proton beam pulses with repetition rate of 1Hz at an average beam power of 300~400W from accelerator collided on the tungsten target.

All systems of the target station were operating smoothly. Continuous cold and thermal neutron pulse from three types of moderator were output for neutron instruments, while the target imaging system successfully captured the proton beam imaging on the target.

Up until 21:00 p.m., detectors of all three Phase-I instruments, including the General-Purpose Powder Diffractometer (GPPD), the Small-Angle Neutron Scattering instrument (SANS) and the Multi-purpose Reflectometer (MR), measured the neutron signals.

The neutron beam was successfully obtained for the first time at the China Spallation Neutron Source (CSNS) on 28th August. This is a great milestone for the CSNS project, marking the completion of the main construction and entering into the test operation phase.


A Joint Beam Commissioning Performed at CSNS---Chinese Academy of Sciences

 

[JSCh]

1st ITER Magnet Component Arrives in Cadarache
Nov 07, 2017

ITER DG Bernard BIGOT hosting the ceremony (Image by Christophe ROUX) ​

The first ITER magnet component, PF4 cryostat feeder through, arrived in Cadarache on 25th October. A ceremony was held in Institute for Magnetic Fusion Research (IRFM) to celebrate this delivery from China.

This magnet feeder system was manufactured by the Institute of Plasma Physics (ASIPP), Hefei Institute of Physical Science, and will be tested on Magnet Infrastructure Facilities for ITER (MIFI) on the French Alternative Energies and Atomic Energy Commission ( CEA) site, before installation on ITER.

At the ceremony, ITER Director General (DG) Bernard Bigot congratulated and thanked China for its partnership, leadership, scientific genuine excellence and, most of all, its commitment to ITER project.

"Yesterday was just the 10th anniversary of ITER. I believe what we are doing is historic!" Director General of ITER China CNDA DG LUO Delong said. "I would express my gratitude to the ASIPP team led by SONG Yuntao".

Feeder is the lifeline of ITER magnet. It carries cryogenic cooling and power supply and plays the role as the transmission line for diagnosis and control signals.

The newly-arrived PF4 CFT is 8.5m long, 4.8m tall and 2.5m wide, consisting of more than 60,000 parts and weighing 16.1 tons. But can we imagine? It is just 1% of the entire Feeder system!

PF4 CFT is also the first magnet component of ITER. It’s the first feeder component to be installed before the ITER cryostat is in place.That’s why its arrival has positive significance to the progress of ITER project.

CEA/IRFM Director Alain Becoulet, ITER Magnet Division head Neil Mitchell and more than 40 scientists and engineers from ITER IO, ASIPP and IRFM also attended the ceremony to welcome the component arriving across seas.



1st ITER Magnet Component Arrives in Cadarache---Chinese Academy of Sciences

 

[Bussard Ramjet]

Today, two papers from China appeared in Nature, (perhaps the highest regarded journal in the world).

There were total of 15 papers in the journal.

The first article, that has already been posted above by @JSCh is completely Chinese:

https://www.nature.com/articles/nature24463

The other article, had 5 authors out of which 3 are Chinese, and 2 appear to be Chinese Americans. (or Chinese citizens in America)

Out of the two lead authors though, one is in China, the other in US.

https://www.nature.com/articles/nature24266

 

[JSCh]

Today, two papers from China appeared in Nature, (perhaps the highest regarded journal in the world).

There were total of 15 papers in the journal.

The first article, that has already been posted above by @JSCh is completely Chinese:

https://www.nature.com/articles/nature24463

The other article, had 5 authors out of which 3 are Chinese, and 2 appear to be Chinese Americans. (or Chinese citizens in America)

Out of the two lead authors though, one is in China, the other in US.

https://www.nature.com/articles/nature24266

The second paper was also posted before here -> https://defence.pk/pdf/threads/china-science-technology-forum.249386/page-116#post-9982308

Also published online,

Binquan Kou, Yixin Cao, Jindong Li, Chengjie Xia, Zhifeng Li, Haipeng Dong, Ang Zhang, Jie Zhang, Walter Kob, Yujie Wang. Granular materials flow like complex fluids. Nature (2017). DOI: 10.1038/nature24062​

Granular materials such as sand, powders and foams are ubiquitous in daily life and in industrial and geotechnical applications1, 2, 3, 4. These disordered systems form stable structures when unperturbed, but in the presence of external influences such as tapping or shear they ‘relax’, becoming fluid in nature. It is often assumed that the relaxation dynamics of granular systems is similar to that of thermal glass-forming systems3, 5. However, so far it has not been possible to determine experimentally the dynamic properties of three-dimensional granular systems at the particle level. This lack of experimental data, combined with the fact that the motion of granular particles involves friction (whereas the motion of particles in thermal glass-forming systems does not), means that an accurate description of the relaxation dynamics of granular materials is lacking. Here we use X-ray tomography to determine the microscale relaxation dynamics of hard granular ellipsoids subject to an oscillatory shear. We find that the distribution of the displacements of the ellipsoids is well described by a Gumbel law6 (which is similar to a Gaussian distribution for small displacements but has a heavier tail for larger displacements), with a shape parameter that is independent of the amplitude of the shear strain and of the time. Despite this universality, the mean squared displacement of an individual ellipsoid follows a power law as a function of time, with an exponent that does depend on the strain amplitude and time. We argue that these results are related to microscale relaxation mechanisms that involve friction and memory effects (whereby the motion of an ellipsoid at a given point in time depends on its previous motion). Our observations demonstrate that, at the particle level, the dynamic behaviour of granular systems is qualitatively different from that of thermal glass-forming systems, and is instead more similar to that of complex fluids. We conclude that granular materials can relax even when the driving strain is weak.​

 

[Bussard Ramjet]

The second paper was also posted before here -> https://defence.pk/pdf/threads/china-science-technology-forum.249386/page-116#post-9982308

Also published online,

Binquan Kou, Yixin Cao, Jindong Li, Chengjie Xia, Zhifeng Li, Haipeng Dong, Ang Zhang, Jie Zhang, Walter Kob, Yujie Wang. Granular materials flow like complex fluids. Nature (2017). DOI: 10.1038/nature24062​

Granular materials such as sand, powders and foams are ubiquitous in daily life and in industrial and geotechnical applications1, 2, 3, 4. These disordered systems form stable structures when unperturbed, but in the presence of external influences such as tapping or shear they ‘relax’, becoming fluid in nature. It is often assumed that the relaxation dynamics of granular systems is similar to that of thermal glass-forming systems3, 5. However, so far it has not been possible to determine experimentally the dynamic properties of three-dimensional granular systems at the particle level. This lack of experimental data, combined with the fact that the motion of granular particles involves friction (whereas the motion of particles in thermal glass-forming systems does not), means that an accurate description of the relaxation dynamics of granular materials is lacking. Here we use X-ray tomography to determine the microscale relaxation dynamics of hard granular ellipsoids subject to an oscillatory shear. We find that the distribution of the displacements of the ellipsoids is well described by a Gumbel law6 (which is similar to a Gaussian distribution for small displacements but has a heavier tail for larger displacements), with a shape parameter that is independent of the amplitude of the shear strain and of the time. Despite this universality, the mean squared displacement of an individual ellipsoid follows a power law as a function of time, with an exponent that does depend on the strain amplitude and time. We argue that these results are related to microscale relaxation mechanisms that involve friction and memory effects (whereby the motion of an ellipsoid at a given point in time depends on its previous motion). Our observations demonstrate that, at the particle level, the dynamic behaviour of granular systems is qualitatively different from that of thermal glass-forming systems, and is instead more similar to that of complex fluids. We conclude that granular materials can relax even when the driving strain is weak.​

Oh, Cool. I missed that.

The second paper was also posted before here -> https://defence.pk/pdf/threads/china-science-technology-forum.249386/page-116#post-9982308

Also published online,

Binquan Kou, Yixin Cao, Jindong Li, Chengjie Xia, Zhifeng Li, Haipeng Dong, Ang Zhang, Jie Zhang, Walter Kob, Yujie Wang. Granular materials flow like complex fluids. Nature (2017). DOI: 10.1038/nature24062​

Granular materials such as sand, powders and foams are ubiquitous in daily life and in industrial and geotechnical applications1, 2, 3, 4. These disordered systems form stable structures when unperturbed, but in the presence of external influences such as tapping or shear they ‘relax’, becoming fluid in nature. It is often assumed that the relaxation dynamics of granular systems is similar to that of thermal glass-forming systems3, 5. However, so far it has not been possible to determine experimentally the dynamic properties of three-dimensional granular systems at the particle level. This lack of experimental data, combined with the fact that the motion of granular particles involves friction (whereas the motion of particles in thermal glass-forming systems does not), means that an accurate description of the relaxation dynamics of granular materials is lacking. Here we use X-ray tomography to determine the microscale relaxation dynamics of hard granular ellipsoids subject to an oscillatory shear. We find that the distribution of the displacements of the ellipsoids is well described by a Gumbel law6 (which is similar to a Gaussian distribution for small displacements but has a heavier tail for larger displacements), with a shape parameter that is independent of the amplitude of the shear strain and of the time. Despite this universality, the mean squared displacement of an individual ellipsoid follows a power law as a function of time, with an exponent that does depend on the strain amplitude and time. We argue that these results are related to microscale relaxation mechanisms that involve friction and memory effects (whereby the motion of an ellipsoid at a given point in time depends on its previous motion). Our observations demonstrate that, at the particle level, the dynamic behaviour of granular systems is qualitatively different from that of thermal glass-forming systems, and is instead more similar to that of complex fluids. We conclude that granular materials can relax even when the driving strain is weak.​

Also do you have some good scientometric study about Chinese research to read? I would like to know Chinese progress in science and its subfields.

I hear that Chinese government released some stats during 19th congress. Can you please help me here?

 

[JSCh]

Oh, Cool. I missed that.




Also do you have some good scientometric study about Chinese research to read? I would like to know Chinese progress in science and its subfields.

I hear that Chinese government released some stats during 19th congress. Can you please help me here?

Sorry, I don't have those info.

 

[Bussard Ramjet]

Sorry, I don't have those info.

Okay. I thought you may have it since you are is interested in research of China.

However, I think that it makes more sense to look at the larger picture than individual articles.

 

[TaiShang]

Chinese scientists identify genetic pathway in aging

By Zhou Wenting in Shanghai (China Daily) 08:54, November 10, 2017

Chinese scientists studying a worm have found the first genetic pathway underlying natural variation in aging, which could provide insights for the development of interventions to slow down the process in humans.

They found that the combination of a certain neuropeptide coding gene and its receptor gene controls the stress reaction of a "longevity gene", which regulates the rate of aging.

The more active the coding gene and the stronger the receptor gene, the more rapid aging occurs, according to the team from the Chinese Academy of Sciences' Institute of Neuroscience.

An article about their study, which took more than five years, was published on Thursday in the journal Nature.

Uncovering the genetic secrets of the aging rate is significant, as the average age of the global population is rising fast. Aging is also a major risk factor for diseases, such as cancers and diabetes, the researchers said.

According to the United Nations, the number of people age 60 or older hit 1 billion worldwide this year and will rise to 3.1 billion by 2100.

"When people live longer, they begin to care more about healthy aging, which means keeping healthy and youthful and having a better quality of life in their twilight years, like some lucky ones do," said Cai Shiqing, the team's lead researcher.

One peer review of the article said the results will be of interest to the readers of Nature because of the general lack of information about how natural genetic variation regulates aging, and the role of neuromodulatory signaling in the process.

Lab experiments were conducted on Caenorhabditis elegans, a transparent worm about 1 millimeter in length that lives in temperate soil environments. It is the basis of the animal model widely used for age-related research because of its clear genetic profile and short life span - an average of three weeks.

The tiny free-living worms from different parts of the world show varied rates of decline in virility, eating and locomotion during aging.

Researchers said they have not yet found the worms' neuropeptide in the human body.

"But we know that animal evolution is conservative, and if we carry on with further studies we're confident that we will probably find that the mechanism underlying the aging rate of mammals is the same as for the worms," said Mu-Ming Poo, director of the institute and an academician of the science academy.

"Healthy human life can be extended if there is a way to target these genes in the future," he said.

http://en.people.cn/n3/2017/1110/c90000-9290957.html

 

[JSCh]

Chinese medicine scholars develop novel targeted delivery system for CRISPR/Cas9
Achieve therapeutic genome editing of VEGFA in osteosarcoma
Date: November 10, 2017
Source: Hong Kong Baptist University

This image shows the preparation of LC09-PPC-CRISPR/Cas9 delivery system.

Credit: HKBU

Chinese Medicine scholars at Hong Kong Baptist University (HKBU) have succeeded in developing a novel targeted delivery system for CRISPR/Cas9 to achieve therapeutic genome editing of VEGFA in osteosarcoma (OS). Their research paper entitled "Tumor cell-targeted delivery of CRISPR/Cas9 by aptamer-functionalised lipopolymer for therapeutic genome editing of VEGFA in osteosarcoma" was recently published in the academic journal Biomaterials.

CRISPR/Cas9 is a budding genome editing technology which holds tremendous promise for cancer treatment. However, a major bottleneck for achieving the therapeutic potential of CRISPR/Cas9 is the lack of an in vivo targeted delivery system. The HKBU team has achieved a breakthrough in the search for an answer to the crux of the above mentioned problem and developed an aptamer-functionalised delivery system for CRISPR/Cas9 with the treatment of OS as a research target.

The research team is led by Professor Lyu Aiping, Dean of the School of Chinese Medicine (SCM) of HKBU, and Professor Zhang Ge, Director of Technology Development Division and Associate Director of Teaching and Research Division of SCM.

Professor Zhang Ge said: "OS, a very common primary malignant bone tumor in children and adolescents, is mainly treated by surgery and chemotherapy but the five-year post-surgery survival rate is a mere 5% to 20%. Aptamers which are single-stranded oligonucleotides and could specifically recognise target cells have been widely used for in vivo targeted delivery of therapeutics. VEGFA has been reported to be a novel therapeutic target for OS."

Professor Lyu Aiping said: "The tumor-specific aptamers, when conjugated with PPC polymers encapsulating CRISPR/Cas9, may facilitate therapeutic genome editing in tumors."

In the experiments using a mouse model, the aptamer facilitated selective distribution of CRISPR/Cas9 in both orthotopic OS and lung metastasis, leading to effective in vivo VEGFA genome editing, inhibited orthotopic OS malignancy and lung metastasis, as well as reduced angiogenesis and bone lesion with no detectable toxicity. The research facilitated clinical application of CRISPR/Cas9 in tumor treatment.

Journal Reference:

1. Chao Liang, Fangfei Li, Luyao Wang, Zong-Kang Zhang, Chao Wang, Bing He, Jie Li, Zhihao Chen, Atik Badshah Shaikh, Jin Liu, Xiaohao Wu, Songlin Peng, Lei Dang, Baosheng Guo, Xiaojuan He, D.W.T. Au, Cheng Lu, Hailong Zhu, Bao-Ting Zhang, Aiping Lu, Ge Zhang. Tumor cell-targeted delivery of CRISPR/Cas9 by aptamer-functionalized lipopolymer for therapeutic genome editing of VEGFA in osteosarcoma. Biomaterials, 2017; 147: 68 DOI: 10.1016/j.biomaterials.2017.09.015

Chinese medicine scholars develop novel targeted delivery system for CRISPR/Cas9: Achieve therapeutic genome editing of VEGFA in osteosarcoma -- ScienceDaily

 

[JSCh]

Focus: Field-Free Spin Patterns
November 10, 2017• Physics 10, 124

A vortex-like magnetic spin structure inside a small disk of material is stable without an external magnetic field and might be useful for information storage or processing.

​

F. Zheng et al., Phys. Rev. Lett. (2017)
Magnetic whorls. A target skyrmion is a pattern of spins in a material (gray disks) that includes two components (shown below each disk): a “normal” circular skyrmion (middle level) and a ring of spins that produces an opposing magnetic field (bottom level). The pattern comes in two states, “down” (left) and “up” (right). ​

Magnetic skyrmions are swirling patterns of spins in a material, and they could potentially be used to store data. They often require an external magnetic field for stability, but a new experiment using a nanosized disk has demonstrated a skyrmion that exists without any external field. The so-called target skyrmion consists of a circular skyrmion surrounded by a thin ring of twisting spins. The researchers show that a magnetic field can switch the system between two different orientations that could represent the zero and one of a digital bit.

Skyrmions come in a number of shapes, but the most familiar looks like a “bad hair day” for a magnetic material. The spins in the center of the skyrmion point up, but as one moves out from the center, the spins gradually rotate in both the horizontal and vertical planes, twisting around like the hairs in a cowlick and ending with the spins pointing down at the outer edge of the circle. This whirling is robust because no uniform rotation (or “combing”) can unwind it. The structure is also compact, with a diameter as small as a few nanometers, which is several times smaller than the ferromagnetic domains currently used in magnetic data storage. Therefore, skyrmion-based memory could offer a higher storage density than traditional ferromagnetic domains, explains Jiadong Zang from the University of New Hampshire in Durham.

Skyrmions appear in various magnetic materials with an asymmetry in their crystal structure that causes nearby spins to tilt relative to each other, rather than aligning in parallel as they do in a ferromagnet. In most cases, the stability of this spin configuration relies on an external magnetic field, which would complicate the control of closely packed skyrmion-based bits. Motivated by theoretical predictions [1–3], a team led by Zang and Haifeng Du of the Hefei Institutes of Physical Science in China has demonstrated the existence of target skyrmions, which are stable in the absence of an external field.


Continue -> Physics - Focus: Field-Free Spin Patterns

Fengshan Zheng, Hang Li, Shasha Wang, Dongsheng Song, Chiming Jin, Wenshen Wei, András Kovács, Jiadong Zang, Mingliang Tian, Yuheng Zhang, Haifeng Du, and Rafal E. Dunin-Borkowski. Direct Imaging of a Zero-Field Target Skyrmion and Its Polarity Switch in a Chiral Magnetic Nanodisk. Phys. Rev. Lett. 119, 197205 (2017). DOI: https://doi.org/10.1103/PhysRevLett.119.197205​

 

[JSCh]

Public Release: 9-Nov-2017
Practical superconducting nanowire single photon detector with record detection efficiency over 90 percent
Science China Press

​

Schematics of fiber-coupled superconducting nanowire single photon detector.
©Science China Press​

Superconducting nanowire single-photon detectors (SNSPDs) offer significant improvement on detection efficiency (DE) compared to their semiconducting counterparts, having enabled many breakthrough applications in quantum information technologies. The team headed by Prof. Lixing You from Shanghai Institute of Microsystem and Information Technology (SIMIT), Chinese Academy of Sciences (CAS) (also affiliated to CAS Center for Excellence in Superconducting Electronics (CENSE)) first demonstrated the fabrication and operation of a NbN-SNSPD with system detection efficiency over 90% at 2.1 K at a wavelength of 1550 nm, which paves the way for practical application of SNSPD (Figure 1).

The results were published recently on SCIENCE CHINA Physics, Mechanics & Astronomy [1] as a cover image story. Dr. Weijun Zhang is the first author and Dr. Lixing You is the corresponding author.

At 1550 nm, which is the most important wavelength for applications, the state of the art SNSPD made of WSi superconductor has reached a DE record of 93% [2], compared to InGaAs detector with DE ~30%. Unfortunately, WSi-SNSPD usually operates at sub-kelvin temperatures, requiring expensive and user unfriendly refrigeration equipment.

Extensive efforts are made on the development of SNSPDs based on NbN, targeted at operating temperature above 2K, accessible to inexpensive and user-friendly compact cryocoolers. With a decade research, the detection efficiency of NbN-SNSPDs were gradually increased to ~ 80%. However, further improvements are not reported. Achieving DE over 90% requires the simultaneous optimization of many different factors, including near perfect optical coupling, near perfect absorption, and near unity intrinsic quantum efficiency. Previous attempts at doing this have mostly been made through a process of trial and error.

This paper first reported a NbN-SNSPD system based on G-M cryocooler with system detection efficiency over 90% (at dark count rate of 10 Hz) at 2.1 K at a wavelength of 1550 nm. The efficiency of the device saturates to 92% when the temperature is lowered to 1.8 K.

The success of this device has been the result of using an integrated Distributed Bragg Reflector (DBR) cavity offering near unity refection at the interface, and through systematic optimization of the NbN nanowire's meandered geometry. The joint efforts enable researchers to simultaneously achieve the stringent requirements for coupling, absorption and intrinsic quantum efficiency. What is more, the device exhibit timing jitters down to 79 ps, almost half that of previously reported WSi-SNSPD, promising additional advantages in applications requiring high timing precision. The devices have been applied to the quantum information frontier experiments in University of Science and Technology of China.

SNSPD with near unity detection efficiency operational on economical and user-friendly compact cryocooler will provide researchers a powerful and easy accessible tool, envisage further breakthrough in quantum information areas such as optical quantum computation/simulation, quantum key distribution etc., in a foreseeable near future. Aiming to this niche and growing market, Dr. You et al also founded a start-up company (Shanghai Photon Technology CO LTD, http://www.sconphoton.com/ ) to commercialize the technology.

The SNSPDs with start-of-art performance from SIMIT have provided key support to quantum communication of China. Collaborated with JW Pan's group, many world records on fiber quantum key distribution have been made including the current record of the longest distance of 404 km [3]. Dr. You believes that there is still room for further improving the detection efficiency of NbN SNSPD. In the new National Key R&D Program of China kicked off in July of 2017 directed by Dr. You, the new target of the detection efficiency is 93-95%.

###​

This research was funded by National Key R&D Program of China (2017YFA0304000); Strategic Priority Research Program (B) of the Chinese Academy of Sciences (XDB04010200); National Natural Science Foundation of China (91121022, 61401441, and 61401443) and the Science and Technology Commission of Shanghai Municipality (16JC1400402)


Practical superconducting nanowire single photon detector with record detection efficiency over 90 percent | EurekAlert! Science News

WeiJun Zhang, LiXing You, Hao Li, Jia Huang, ChaoLin Lv, Lu Zhang, XiaoYu Liu, JunJie Wu, Zhen Wang, XiaoMing Xie, NbN superconducting nanowire single photon detector with efficiency over 90% at 1550 nm wavelength operational at compact cryocooler temperature, Science China Physics, Mechanics & Astronomy (2017). DOI: 10.1007/s11433-017-9113-4​

 

[JSCh]

10-Qubit Entanglement and Parallel Logic Operations with a Superconducting Circuit

Abstract
Here we report on the production and tomography of genuinely entangled Greenberger-Horne-Zeilinger states with up to ten qubits connecting to a bus resonator in a superconducting circuit, where the resonator-mediated qubit-qubit interactions are used to controllably entangle multiple qubits and to operate on different pairs of qubits in parallel. The resulting 10-qubit density matrix is probed by quantum state tomography, with a fidelity of 0.668±0.025. Our results demonstrate the largest entanglement created so far in solid-state architectures and pave the way to large-scale quantum computation.​

Chao Song, Kai Xu, Wuxin Liu, Chui-ping Yang, Shi-Biao Zheng, Hui Deng, Qiwei Xie, Keqiang Huang, Qiujiang Guo, Libo Zhang, Pengfei Zhang, Da Xu, Dongning Zheng, Xiaobo Zhu, H. Wang, Y.-A. Chen, C.-Y. Lu, Siyuan Han, Jian-Wei Pan. 10-Qubit Entanglement and Parallel Logic Operations with a Superconducting Circuit. Phys. Rev. Lett. (2017). DOI: https://doi.org/10.1103/PhysRevLett.119.180511

Superconducting quantum computer achieves ten-qubit entanglement
Nov 10, 2017

Entangled states: a ten-qubit processor​

Physicists in China and the US have built a ten-qubit superconducting quantum processor that could be scaled up to tackle problems not solvable by classical computers. The performance of the device was verified using quantum tomography, which showed that the new approach can generate a true ten-partite Greenberger–Horne–Zeilinger (GHZ) state – the largest yet achieved in a solid-state system.

The field of quantum computing is in its infancy, and a genuinely useful, practical device that outperforms classical computers has not yet been built. At this stage of development, researchers do not even agree on the basics of implementation, but techniques employing superconducting circuits have an advantage over some other designs in that they are based on established and scalable microfabrication processes.

Robust to noise
Writing in Physical Review Letters, a multi-institution collaboration led by Jian-Wei Pan of the University of Science and Technology of China, Shanghai, report a superconducting architecture in which information is encoded as transmons – a form of charge qubit especially robust to noise. The team used a bus resonator to mediate qubit–qubit coupling, and showed that a single collective interaction could produce a ten-qubit GHZ state from initially non-entangled qubits.

Pan and colleagues propose that the efficient generation of entanglement, and the ability to operate on different qubit pairs in parallel, make their approach a promising route to achieving a large-scale quantum computer.

About the author
Marric Stephens is a reporter on physicsworld.com


Superconducting quantum computer achieves ten-qubit entanglement - physicsworld.com

 

[Bussard Ramjet]

Superconducting quantum computer achieves ten-qubit entanglement
Nov 10, 2017

Entangled states: a ten-qubit processor​

Physicists in China and the US have built a ten-qubit superconducting quantum processor that could be scaled up to tackle problems not solvable by classical computers. The performance of the device was verified using quantum tomography, which showed that the new approach can generate a true ten-partite Greenberger–Horne–Zeilinger (GHZ) state – the largest yet achieved in a solid-state system.

The field of quantum computing is in its infancy, and a genuinely useful, practical device that outperforms classical computers has not yet been built. At this stage of development, researchers do not even agree on the basics of implementation, but techniques employing superconducting circuits have an advantage over some other designs in that they are based on established and scalable microfabrication processes.

Robust to noise
Writing in Physical Review Letters, a multi-institution collaboration led by Jian-Wei Pan of the University of Science and Technology of China, Shanghai, report a superconducting architecture in which information is encoded as transmons – a form of charge qubit especially robust to noise. The team used a bus resonator to mediate qubit–qubit coupling, and showed that a single collective interaction could produce a ten-qubit GHZ state from initially non-entangled qubits.

Pan and colleagues propose that the efficient generation of entanglement, and the ability to operate on different qubit pairs in parallel, make their approach a promising route to achieving a large-scale quantum computer.

About the author
Marric Stephens is a reporter on physicsworld.com


Superconducting quantum computer achieves ten-qubit entanglement - physicsworld.com

This is not an American collaboration paper. This is a purely Chinese paper. Only 1 author out of 19 is an American. The lead author, the last author, and all the corresponding authors are Chinese.