Soheil_Esy
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2015-05-13
Scientists may be one step closer to solving some of the biggest mysteries of the universe as a neutrino experiment in southern China returned promising results.
A team from China's National Supercomputer Center in Guangzhou using the world's fastest supercomputer Tianhe-2 have completed a simulation involving three trillion neutrinos and dark matter particles.
Zhang Tongjie of Beijing Normal University and lead researcher of the project, has described a "video" simulating the elongated evolution of the universe, produced thanks to Tianhe-2, which worked like a "high-speed camera with extremely high definition".
The supercomputer had "opened a new door" to the study of neutrinos, which could greatly expedite understanding of the origin and evolution of the universe, Zhang said.
Neutrinos are sometimes known as "ghost particles" because they interact so weakly with other forms of matter. They are among the most abundant - and least understood - fundamental particles. To figure out how they work, their mass must be established, but this has never been done accurately.
"At this moment, Tianhe-2 is the only supercomputer capable of conducting such an experiment," he said.
Tianhe-2, which literally means "Milky Way-2", took the top spot on a2013 list of supercomputers. It is able to operate at 33.86 petaflops per second, 33,860 quadrillion calculations.
Tianhe-2 could hold the world's fastest supercomputer title till 2018, when the US is expected unveil two supercomputers three to five times faster than the Chinese system, at a cost of $325 million.
Video
https://www.youtube.com/watch?feature=player_embedded&v=FJrVAp-0Y8A
at 1m40s
http://www.chinadaily.com.cn/china/2015-05/13/content_20709568.htm
Scientists may be one step closer to solving some of the biggest mysteries of the universe as a neutrino experiment in southern China returned promising results.
A team from China's National Supercomputer Center in Guangzhou using the world's fastest supercomputer Tianhe-2 have completed a simulation involving three trillion neutrinos and dark matter particles.
Zhang Tongjie of Beijing Normal University and lead researcher of the project, has described a "video" simulating the elongated evolution of the universe, produced thanks to Tianhe-2, which worked like a "high-speed camera with extremely high definition".
The supercomputer had "opened a new door" to the study of neutrinos, which could greatly expedite understanding of the origin and evolution of the universe, Zhang said.
Neutrinos are sometimes known as "ghost particles" because they interact so weakly with other forms of matter. They are among the most abundant - and least understood - fundamental particles. To figure out how they work, their mass must be established, but this has never been done accurately.
"At this moment, Tianhe-2 is the only supercomputer capable of conducting such an experiment," he said.
Tianhe-2, which literally means "Milky Way-2", took the top spot on a2013 list of supercomputers. It is able to operate at 33.86 petaflops per second, 33,860 quadrillion calculations.
Tianhe-2 could hold the world's fastest supercomputer title till 2018, when the US is expected unveil two supercomputers three to five times faster than the Chinese system, at a cost of $325 million.
Video
https://www.youtube.com/watch?feature=player_embedded&v=FJrVAp-0Y8A
at 1m40s
http://www.chinadaily.com.cn/china/2015-05/13/content_20709568.htm
N-body simulation of neutrinos and large scale structure of the universe
Background:
In recent years, depending of the best instruments, many sciences groups make lots of top researches in the world in our country. For example, one of them is the Daya Bay Reactor Neutrino Experiment, which is in the Daya Bay nuclear power station, has measured a best nonzero value for the neutrino mixing angle around the world (Phys. Rev. Lett. 108, 2012. 171803). In this instance, the neutrino numerical simulation group use TianHe2 to simulate a top computational physics topic in the world. On a 0.1h/Mpc scale, the evolvement of neutrino entangles with the nonlinear dark matter cluster, which causes a too large computation complexity. In this fact, the statistical calculation of them is a challenge (Y. Ali-Haimoud and S. Bird, MNRAS 428, 3375 (2013), 1209.0461).
In 2015, the group used a total of 331776 cores(13824 nodes) to simulate two topics: 1) the inversion of 3 trillion dark matter particles and 2) the inversion of 3 trillion dark matter with neutrino from now to the big bang. The number of particles of these two simulations is twice the previous world record. The group hopes the research helps scientists to make more accurate predictions of the evolution of neutrino.
Software：
CubeP3M
Result:
http://www.nscc-gz.cn/en/Application_Domains/ESEE/Cases/2015/0309/439.html
Neutrinos are one of the known existing dark matter particles, and neutrino masses have an effect on the large scale structure of the Universe. Weak gravitational lensing surveys in the very near future may be able to achieve enough accuracy and to give the first constraint on the neutrino mass. Combining neutrino and dark matter evolution is highly non-linear, and computer simulations are highly time- and memory-consuming. We have run the open-source cosmological code CubeP3M on the world’s fastest super computer, ranking 1st in TOP500, Tianhe-2 (TH2). The figure below shows the dark matter + neutrino N-body simulation (2D projection) of the large scale structure of the Universe. We can see that the dark matter (black) and neutrino (orange) distributions are correlated on large scales. This research project is also supported by Canadian Institute for Theoretical Astrophysics; Department of Astronomy, Beijing Normal University; Guangzhou National Super Computing Center.
http://kiaa.pku.edu.cn/people/hao-ran-yu
