时空晶体可使钟永久保持精准走时
文章来源:未知 文章作者:enread 发布时间:2012-09-26 06:17 字体: [ ]  进入论坛
(单词翻译:双击或拖选)
Imagine a clock that will keep perfect time forever, even after the heat-death of the universe. This is the "wow" factor behind a device known as a "space-time crystal," a four-dimensional crystal that has periodic structure in time as well as space. However, there are also practical and important scientific reasons for constructing a space-time crystal. With such a 4D crystal, scientists would have a new and more effective means by which to study how complex physical properties and behaviors emerge from the collective interactions of large numbers of individual particles, the so-called many-body problem of physics. A space-time crystal could also be used to study phenomena1 in the quantum world, such as entanglement2(纠缠,牵连), in which an action on one particle impacts another particle even if the two particles are separated by vast distances.
 
A space-time crystal, however, has only existed as a concept in the minds of theoretical scientists with no serious idea as to how to actually build one -- until now. An international team of scientists led by researchers with the U.S. Department of Energy (DOE)'s Lawrence Berkeley National Laboratory (Berkeley Lab) has proposed the experimental design of a space-time crystal based on an electric-field ion trap and the Coulomb repulsion of particles that carry the same electrical charge.
 
"The electric field of the ion trap holds charged particles in place and Coulomb repulsion causes them to spontaneously form a spatial3(空间的) ring crystal," says Xiang Zhang, a faculty4 scientist with Berkeley Lab's Materials Sciences Division who led this research. "Under the application of a weak static magnetic field, this ring-shaped ion crystal will begin a rotation5 that will never stop. The persistent6 rotation of trapped ions produces temporal order, leading to the formation of a space-time crystal at the lowest quantum energy state."
 
Because the space-time crystal is already at its lowest quantum energy state, its temporal order -- or timekeeping -- will theoretically persist even after the rest of our universe reaches entropy, thermodynamic equilibrium7(热力学平衡) or "heat-death."
 
Zhang, who holds the Ernest S. Kuh Endowed Chair Professor of Mechanical Engineering at the University of California (UC) Berkeley, where he also directs the Nano-scale Science and Engineering Center, is the corresponding author of a paper describing this work in Physical Review Letters (PRL). The paper is titled "Space-time crystals of trapped ions." Co-authoring this paper were Tongcang Li, Zhe-Xuan Gong, Zhang-Qi Yin, Haitao Quan, Xiaobo Yin, Peng Zhang and Luming Duan.
 
The concept of a crystal that has discrete8(不连续的) order in time was proposed earlier this year by Frank Wilczek, the Nobel-prize winning physicist9 at the Massachusetts Institute of Technology. While Wilczek mathematically proved that a time crystal can exist, how to physically10 realize such a time crystal was unclear. Zhang and his group, who have been working on issues with temporal order in a different system since September 2011, have come up with an experimental design to build a crystal that is discrete both in space and time -- a space-time crystal. Papers on both of these proposals appear in the same issue of PRL (September 24, 2012).


点击收听单词发音收听单词发音  

1 phenomena 8N9xp     
n.现象
参考例句:
  • Ade couldn't relate the phenomena with any theory he knew.艾德无法用他所知道的任何理论来解释这种现象。
  • The object of these experiments was to find the connection,if any,between the two phenomena.这些实验的目的就是探索这两种现象之间的联系,如果存在着任何联系的话。
2 entanglement HoExt     
n.纠缠,牵累
参考例句:
  • This entanglement made Carrie anxious for a change of some sort.这种纠葛弄得嘉莉急于改变一下。
  • There is some uncertainty about this entanglement with the city treasurer which you say exists.对于你所说的与市财政局长之间的纠葛,大家有些疑惑。
3 spatial gvcww     
adj.空间的,占据空间的
参考例句:
  • This part of brain judges the spatial relationship between objects.大脑的这部分判断物体间的空间关系。
  • They said that time is the feeling of spatial displacement.他们说时间是空间位移的感觉。
4 faculty HhkzK     
n.才能;学院,系;(学院或系的)全体教学人员
参考例句:
  • He has a great faculty for learning foreign languages.他有学习外语的天赋。
  • He has the faculty of saying the right thing at the right time.他有在恰当的时候说恰当的话的才智。
5 rotation LXmxE     
n.旋转;循环,轮流
参考例句:
  • Crop rotation helps prevent soil erosion.农作物轮作有助于防止水土流失。
  • The workers in this workshop do day and night shifts in weekly rotation.这个车间的工人上白班和上夜班每周轮换一次。
6 persistent BSUzg     
adj.坚持不懈的,执意的;持续的
参考例句:
  • Albert had a persistent headache that lasted for three days.艾伯特连续头痛了三天。
  • She felt embarrassed by his persistent attentions.他不时地向她大献殷勤,使她很难为情。
7 equilibrium jiazs     
n.平衡,均衡,相称,均势,平静
参考例句:
  • Change in the world around us disturbs our inner equilibrium.我们周围世界的变化扰乱了我们内心的平静。
  • This is best expressed in the form of an equilibrium constant.这最好用平衡常数的形式来表示。
8 discrete 1Z5zn     
adj.个别的,分离的,不连续的
参考例句:
  • The picture consists of a lot of discrete spots of colour.这幅画由许多不相连的色点组成。
  • Most staple fibers are discrete,individual entities.大多数短纤维是不联系的单独实体。
9 physicist oNqx4     
n.物理学家,研究物理学的人
参考例句:
  • He is a physicist of the first rank.他是一流的物理学家。
  • The successful physicist never puts on airs.这位卓有成就的物理学家从不摆架子。
10 physically iNix5     
adj.物质上,体格上,身体上,按自然规律
参考例句:
  • He was out of sorts physically,as well as disordered mentally.他浑身不舒服,心绪也很乱。
  • Every time I think about it I feel physically sick.一想起那件事我就感到极恶心。
TAG标签: time clock space
发表评论
请自觉遵守互联网相关的政策法规,严禁发布色情、暴力、反动的言论。
评价:
表情:
验证码:点击我更换图片