中国科学家首次发现Weyl费米子:低能耗电子传输

兔子发财了

干得漂亮。继续不要停。

高大尚!!!

正格好消息，祝贺祝贺

这些汉字和字母我都认识，组合在以一起就看不懂了，不过是个进步就支持。

虽然我看不懂 ，但是文章所说的拓扑绝缘体”和“量子反常霍尔效应这两个都是货真价实的诺贝尔奖级别的重大成果 只不过 原始理论创新都不是中国提出的，所以中国科学家拿奖的希望不是很大，如果这个成果真的是和前两个是一个级别的  而且从理论到成果都是中国人首创 ，那诺贝尔奖应该是没跑的了

十月赞歌 发表于 2015-7-20 10:12
兔子发财了
为何发财？不解

虽然都是中文，但连起来还是看不懂

应该是准粒子态，可以用来构造量子比特？

那四个字母咋个读啊

看不懂，但能降低功耗这一点肯定是很有价值的

如果以后出现的是费米子计算机，那就有趣了。光量子计算生不逢时呀。。。

兹瓷一下，科学无国界，人类共同的财富

基础科学的每一个进步都值得表扬。

虽然不懂，但看来很NB

牛逼，加油。
粒子手性与反物质或者暗物质有无关联？

不懂，但觉得应该是能获得诺贝尔奖的发现吧

高大上！上海同步光源作为上海人如雷贯耳，但一直以为没什么用。。。

这种东西没啥实际效果，还是给西部人民送馒头，让美帝先搞就行了，何必投入太多！

这仅仅是发现，之前已有理论，可以算么

这坛里估计能看懂的人没几个吧

是不是以后有希望能将手机等电子产品的能耗成百倍地降低？

一说到中国在某方面落后发达国家，通常看到一句评论，别人在这方面有几十年的积累，我们没法比。如果我们现在不积累，几十年后，我们的子孙也只能靠这句评论来给自己作借口。

不懂，赞一下。

http://www.iflscience.com/physic ... tionize-electronics

PHYSICS

Discovery Of Massless Weyl Fermion Particle Could Revolutionize Electronics

July 17, 2015 | by Jonathan O'Callaghan
An illustration of what a Weyl fermion might look like
photo credit: Weyl fermions are essentially "holes" where other electrons would appear. Shutterstock/general-fmv
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Two separate teams of researchers have found evidence for a theorized type of massless particle known as a “Weyl fermion.” The discovery was made by scientists at Princeton University in New Jersey and the Massachusetts Institute of Technology, and could herald a whole new age of better electronics.

Weyl fermions were first hypothesized by German mathematician and physicist Hermann Weyl in 1929. They were proposed as being among the building blocks of subatomic particles, and were also said to be unique in that they would have no mass and also behave as both matter and antimatter – which has the same mass but opposite charge and other properties to regular matter – inside a crystal.

Initially, they were wrongly identified as neutrinos, until it was found in 1998 that neutrinos have a very small amount of mass. Now the researchers say they have solved the 85-year-old mystery for good. The research by both teams was published in the journal Science.

They found the fermions independently by firing photons at crystals of a semi-metal called tantalum arsenide, which has properties between an insulator and a conductor. They cannot exist by themselves as standalone particles, but instead exist as quasiparticles – a "disturbance" in a medium that behaves like a particle. “In other words, they are electronic activity that behaves as if they were particles in free space,” IEEE explains.

But they are important, because Weyl fermions are very stable, and they will also only interact with other Weyl fermions, staying on the same course and at the same speed until they do. This means that, for example, they can carry a charge for long distances without getting scattered and creating heat, like electrons, according to Live Science.

“The physics of the Weyl fermion are so strange, there could be many things that arise from this particle that we're just not capable of imagining now,” said co-author Zahid Hasan, a Princeton professor of physics who led the research team, in a statement.



Hasan, pictured, and his team using a scanning tunneling spectromicroscope to find the Weyl fermion. Danielle Alio/Princeton University.

Particles are essentially divided into two groups. Fermions are said to be those that make up matter, while bosons are the force particles that hold them together. All other fermions are known to have mass, making the Weyl fermion unique among its “peers.”

And its unique properties could make it incredibly useful for electronics in the future, including the development of quantum computing, Hasan told IFLScience. For one thing, they can move independently of one another, and they can also create massless electrons. The consequence is they could flow more easily and lose less heat, making electrons more efficient. "It's like they have their own GPS and steer themselves without scattering," Hasan added in the statement.

More research will be needed in the future to determine just how useful Weyl fermions could turn out to be.

http://phys.org/news/2015-07-yea ... on-electronics.html

After 85-year search, massless particle with promise for next-generation electronics found
July 16, 2015
After 85-year search, massless particle with promise for next-generation electronics found
A detector image (top) signals the existence of Weyl fermions. The plus and minus signs note whether the particle's spin is in the same direction as its motion -- which is known as being right-handed -- or in the opposite direction in which it moves, or left-handed. This dual ability allows Weyl fermions to have high mobility. A schematic (bottom) shows how Weyl fermions also can behave like monopole and antimonopole particles when inside a crystal, meaning that they have opposite magnetic-like charges can nonetheless move independently of one another, which also allows for a high degree of mobility. Credit: Su-Yang Xu and M. Zahid Hasan, Princeton Department of Physics
An international team led by Princeton University scientists has discovered Weyl fermions, an elusive massless particle theorized 85 years ago. The particle could give rise to faster and more efficient electronics because of its unusual ability to behave as matter and antimatter inside a crystal, according to new research.


The researchers report in the journal Science July 16 the first observation of Weyl fermions, which, if applied to next-generation electronics, could allow for a nearly free and efficient flow of electricity in electronics, and thus greater power, especially for computers, the researchers suggest.
Proposed by the mathematician and physicist Hermann Weyl in 1929, Weyl fermions have been long sought by scientists because they have been regarded as possible building blocks of other subatomic particles, and are even more basic than the ubiquitous, negative-charge carrying electron (when electrons are moving inside a crystal). Their basic nature means that Weyl fermions could provide a much more stable and efficient transport of particles than electrons, which are the principle particle behind modern electronics. Unlike electrons, Weyl fermions are massless and possess a high degree of mobility; the particle's spin is both in the same direction as its motion—which is known as being right-handed—and in the opposite direction in which it moves, or left-handed.
"The physics of the Weyl fermion are so strange, there could be many things that arise from this particle that we're just not capable of imagining now," said corresponding author M. Zahid Hasan, a Princeton professor of physics who led the research team.
The researchers' find differs from the other particle discoveries in that the Weyl fermion can be reproduced and potentially applied, Hasan said. Typically, particles such as the famous Higgs boson are detected in the fleeting aftermath of particle collisions, he said. The Weyl fermion, however, was discovered inside a synthetic metallic crystal called tantalum arsenide that the Princeton researchers designed in collaboration with researchers at the Collaborative Innovation Center of Quantum Matter in Beijing and at National Taiwan University.
The Weyl fermion possesses two characteristics that could make its discovery a boon for future electronics, including the development of the highly prized field of efficient quantum computing, Hasan explained.
For a physicist, the Weyl fermions are most notable for behaving like a composite of monopole- and antimonopole-like particles when inside a crystal, Hasan said. This means that Weyl particles that have opposite magnetic-like charges can nonetheless move independently of one another with a high degree of mobility.


The researchers also found that Weyl fermions can be used to create massless electrons that move very quickly with no backscattering, wherein electrons are lost when they collide with an obstruction. In electronics, backscattering hinders efficiency and generates heat. Weyl electrons simply move through and around roadblocks, Hasan said.
After 85-year search, massless particle with promise for next-generation electronics found
Hasan (pictured) and his research group researched and simulated dozens of crystal structures before finding the one suitable for holding Weyl fermions. Once fashioned, the crystals were loaded into this two-story device known as a scanning tunneling spectromicroscope to ensure that they matched theoretical specifications. Located in the Laboratory for Topological Quantum Matter and Spectroscopy in Princeton's Jadwin Hall, the spectromicroscope is cooled to near absolute zero and suspended from the ceiling to prevent even atom-sized vibrations. Credit: Danielle Alio, Office of Communications
"It's like they have their own GPS and steer themselves without scattering," Hasan said. "They will move and move only in one direction since they are either right-handed or left-handed and never come to an end because they just tunnel through. These are very fast electrons that behave like unidirectional light beams and can be used for new types of quantum computing."
Prior to the Science paper, Hasan and his co-authors published a report in the journal Nature Communications in June that theorized that Weyl fermions could exist in a tantalum arsenide crystal. Guided by that paper, the researchers used the Princeton Institute for the Science and Technology of Materials (PRISM) and Laboratory for Topological Quantum Matter and Spectroscopy in Princeton's Jadwin Hall to research and simulate dozens of crystal structures before seizing upon the asymmetrical tantalum arsenide crystal, which has a differently shaped top and bottom.
The crystals were then loaded into a two-story device known as a scanning tunneling spectromicroscope that is cooled to near absolute zero and suspended from the ceiling to prevent even atom-sized vibrations. The spectromicroscope determined if the crystal matched the theoretical specifications for hosting a Weyl fermion. "It told us if the crystal was the house of the particle," Hasan said.
The Princeton team took the crystals passing the spectromicroscope test to the Lawrence Berkeley National Laboratory in California to be tested with high-energy accelerator-based photon beams. Once fired through the crystal, the beams' shape, size and direction indicated the presence of the long-elusive Weyl fermion.
First author Su-Yang Xu, a postdoctoral research associate in Princeton's Department of Physics, said that the work was unique for encompassing theory and experimentalism.
"The nature of this research and how it emerged is really different and more exciting than most of other work we have done before," Xu said. "Usually, theorists tell us that some compound might show some new or interesting properties, then we as experimentalists grow that sample and perform experiments to test the prediction. In this case, we came up with the theoretical prediction ourselves and then performed the experiments. This makes the final success even more exciting and satisfying than before."
In pursuing the elusive particle, the researchers had to pull from a number of disciplines, as well as just have faith in their quest and scientific instincts, Xu said.
"Solving this problem involved physics theory, chemistry, material science and, most importantly, intuition," he said. "This work really shows why research is so fascinating, because it involved both rational, logical thinking, and also sparks and inspiration."
Weyl, who worked at the Institute for Advanced Study, suggested his fermion as an alternative to the theory of relativity proposed by his colleague Albert Einstein. Although that application never panned out, the characteristics of his theoretical particle intrigued physicists for nearly a century, Hasan said. Actually observing the particle was a trying process—one ambitious experiment proposed colliding high-energy neutrinos to test if the Weyl fermion was produced in the aftermath, he said.
The hunt for the Weyl fermion began in the earliest days of quantum theory when physicists first realized that their equations implied the existence of antimatter counterparts to commonly known particles such as electrons, Hasan said.
"People figured that although Weyl's theory was not applicable to relativity or neutrinos, it is the most basic form of fermion and had all other kinds of weird and beautiful properties that could be useful," he said.
"After more than 80 years, we found that this fermion was already there, waiting. It is the most basic building block of all electrons," he said. "It is exciting that we could finally make it come out following Weyl's 1929 theoretical recipe."
Ashvin Vishwanath, a professor of physics at the University of California-Berkeley who was not involved in the study, commented, "Professor Hasan's experiments report the observation of both the unusual properties in the bulk of the crystal as well as the exotic surface states that were theoretically predicted. While it is early to say what practical implications this discovery might have, it is worth noting that Weyl materials are direct 3-D electronic analogs of graphene, which is being seriously studied for potential applications."
Explore further: Third research team close to creating Majorana fermion
More information: "Discovery of a Weyl Fermion semimetal and topological Fermi arcs", www.sciencemag.org/lookup/doi/10.1126/science.aaa9297

米诺夫斯基粒子。。。。。。

http://spectrum.ieee.org/tech-ta ... -faster-electronics

Weyl Fermions Found, a Quasiparticle That Acts Like a Massless Electron

By Charles Q. Choi
Posted 16 Jul 2015 | 18:00 GMT
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Photo: Danielle Alio/Princeton University
After an 85-year hunt, scientists have detected an exotic particle, the “Weyl fermion,” which they suggest could lead to faster and more efficient electronics and to new types of quantum computing.

Electrons, protons, and neutrons belong to a class of particles known as fermions. Unlike the other major class of particles, the bosons, which include photons, fermions can collide with each other—no two fermions can share the same state at the same position at the same time.

Whereas electrons and all the other known fermions have mass, in 1929, mathematician and physicist Hermann Weyl theorized that massless fermions that carry electric charge could exist, so-called Weyl fermions. “Weyl fermions are basic building blocks; you can combine two Weyl fermions to make an electron,” says condensed matter physicist Zahid Hasan at Princeton University.

The fact that Weyl fermions have no mass suggests they could shuffle electric charge along inside electronics far more quickly than electrons can. Another potentially useful quality of Weyl fermions is that they cannot move backward—instead of bouncing away from obstacles, they zip through or around roadblocks. In contrast, electrons can scatter backward when they collide with obstructions, hindering the efficiency of their flow and generating heat.

“Weyl fermions could be used to solve the traffic jams that you get with electrons in electronics—they can move in a much more efficient, ordered way than electrons,” Hasan says. “They could lead to a new type of electronics we call ‘Weyltronics.’”

Electricity in these crystals can move at least twice as fast as it does in graphene and 1,000 times faster than in conventional semiconductors
For decades, physicists thought that subatomic particles called neutrinos were Weyl fermions. However, in 1998, scientists discovered neutrinos do have mass. (Their antimatter equivalent, the antineutrino could be a key technology in ensuring Iran’s compliance in this week’s nuclear deal.)

Now, after 85 years, scientists have finally detected Weyl fermions within in large crystals of tantalum arsenide. They detailed their findings this week online in the journal Science.

Particles such as the famous Higgs boson are often detected in the aftermath of high-energy particle collisions, but in a study published in June the researchers theorized that Weyl fermions could exist in certain crystals known as “Weyl semimetals,” which can essentially split electrons inside into pairs of Weyl fermions that move in opposite directions, Hasan says.

The researchers noted these Weyl fermions are not freestanding particles. Instead, they are quasiparticles that can only exist within those crystals. In other words, they are electronic activity that behaves as if they were particles in free space. By shining beams of ultraviolet light and X-rays at these crystals, the researchers detected the telltale effects of Weyl fermions on those beams.

“These results are very exciting for me personally, since I've been involved significantly in the theoretical discovery of Weyl semimetals a few years ago,” says physicist Anton Burkov at the University of Waterloo, who did not take part in this research. “It’s very exciting to finally see them discovered experimentally in real materials.”

The way that Weyl fermions are constrained from moving backwards is similar to how electrons behave in exotic materials called topological insulators. Such constraints can help current flow highly efficiently; Hasan says that electricity in these crystals can (theoretically) move at least twice as fast as it does in graphene and 1,000 times faster than in conventional semiconductors, “and the crystals can be improved to do even better.” The upshot could be faster electronics that consume less energy. “Power consumption and associated heating is what currently limits a further increase in processor speed in our computers,” Burkov says.

In addition, Weyl fermions could also lead to new kinds of quantum computers that are more resistant to disruption. Quantum computers rely on states known as superpositions, in which a bit can essentially represent both one and zero at the same time. Superpositions offer the chance to solve previously intractable problems, but they are notoriously prone to collapsing  if they interact with the environment. The fact that Weyl fermions are less prone to interacting with their surroundings could lead to new ways of encoding quantum information, Hasan says.

The researchers are now investigating other materials in which Weyl fermions could exist. “We’ve found a niobium-based material, and a silicon-based crystal,” Hasan says.

看不懂，先顶

其实是两个小组同时做出来的，另一个是普林斯顿的。
普林斯顿的文章已经发在了science上，物理所的文章已经发在了prx上。
普林斯顿同时在nature communications上已经发了一篇，据说物理所将要在nature physics上再来一篇。
这个时候有第三个组声称做出了更进一步的东西，也已经发在了science上。

一说到中国在某方面落后发达国家，通常看到一句评论，别人在这方面有几十年的积累，我们没法比。如果我们现 ...
中国有些小钱钱了，就要在基础原创科学方面砸钱。不然跟发达国家的科技差距越拉越大。幸好这些年逐渐有可喜的成果。希望再接再厉。

基础科学每进一步都会对社会造成巨大影响

其实是两个小组同时做出来的，另一个是普林斯顿的。
普林斯顿的文章已经发在了science上，物理所的文章已 ...
国内有什么单位研究量子计算机吗？

物理所的老狗 发表于 2015-7-20 11:46
其实是两个小组同时做出来的，另一个是普林斯顿的。
普林斯顿的文章已经发在了science上，物理所的文章已 ...
哪个第三组？什么更进一步的东西？

有没有经济价值其实不重要，推动基础科学的大进步，最大好处是可以留住高端人才，慢慢的由点及面，大量高尖人才的聚集，可以改变整个国家的科技面貌

其实是两个小组同时做出来的，另一个是普林斯顿的。
普林斯顿的文章已经发在了science上，物理所的文章已 ...
貌似你很了解，难道真如你的ID和物理所有关系？

十月赞歌 发表于 2015-7-20 10:12
兔子发财了
炸药将不用想了 兔子自己弄一个吧

我有知识我自豪 发表于 2015-7-20 11:24
这坛里估计能看懂的人没几个吧
还是不少的。