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Primeur weekly 2015-11-09

Special

HARNESS explored principles to integrate heterogeneous resources into Cloud platform ...

Focus

Combining the benefits of both GPU and CPU in heterogeneous computing ...

Exascale supercomputing

Towards future supercomputing: EU project Exa2Green improves energy efficiency in high performance computing ...

DEEP project unveils next-generation HPC platform ...

Focus on Europe

Launch of BioExcel - Centre of Excellence for Biomolecular Research ...

Information security community for e-infrastructures crystalises at WISE workshop ...

ALCF helps tackle the Large Hadron Collider's Big Data challenge ...

Middleware

Bright Computing to release updates to popular management software at SC15 ...

Altair partners with South Africa's Centre for High Performance Computing ...

Cray, AMPLab, NERSC collaboration targets Spark performance on HPC platforms ...

Hardware

Singapore scientists among the first to benefit from Infinera Cloud Xpress with 100 GbE for data centre interconnect ...

Supermicro world record performance benchmarks for SYS-1028GR-TR with Intel Xeon Phi coprocessors announced at Fall 2015 STAC Summit ...

IBM Teams with Mellanox to help maximize performance of Power Systems LC line servers for Cloud and cluster deployments ...

LSU deploys new IBM supercomputer "Delta" to advance Big Data research in Louisiana ...

Applications

Nomadic computing speeds up Big Data analytics ...

Clemson researchers and IT scientists team up to tackle Big Data ...

Calcium-48's 'neutron skin' thinner than previously thought ...

Oklahoma University collaborating in NSF South Big Data Regional Innovation Hub ...

Columbia to lead Northeast Big Data Innovation Hub ...

University of Miami gets closer to helping find a cure for gastrointestinal cancer thanks to DDN storage ...

The Cloud

Cornell leads new National Science Foundation federated Cloud project ...

Bright Computing reveals plans for Cloud Expo Frankfurt ...

UberCloud delivers CAE Applications as a Service ...

IBM plans to acquire The Weather Company's product and technology businesses; extends power of Watson to the Internet of Things ...

Oracle updates Oracle Cloud Infrastructure services ...

Calcium-48's 'neutron skin' thinner than previously thought

Conceptual art connects the atomic underpinnings of the neutron-rich calcium-48 nucleus with the Crab Nebula, which has a neutron star at its heart. Zeros and ones depict the computational power needed to explore objects that differ in size by 18 orders of magnitude. Image credit: Oak Ridge National Laboratory, U.S. Dept. of Energy; conceptual art by LeJean Hardin and Andy Sproles2 Nov 2015 Oak Ridge - An international team led by Gaute Hagen of the Department of Energy's Oak Ridge National Laboratory used America's most powerful supercomputer, Titan, to compute the neutron distribution and related observables of calcium-48, an isotope with an atomic nucleus consisting of 20 protons and 28 neutrons. Computing the nucleus from first principles revealed that the difference between the radii of neutron and proton distributions - called the "neutron skin" - is considerably smaller than previously thought. The collaboration also made predictions for physical quantities that are current targets of precision measurements. These calculations also impact the size of a neutron star, thereby connecting objects that differ in size by 18 orders of magnitude. The work is published in the journalNature Physics.

"We built a nucleus from scratch from its basic constituents - protons and neutrons", stated Gaute Hagen, a theoretical physicist who initiated and led the project with an award from DOE's Office of Science Early Career Research Programme. "To solve this strongly correlated system of 48 nucleons is far from trivial, because it is a complicated quantum mechanical many-body problem. Many things had to come together - accurate nuclear forces, sophisticated computational algorithms and a powerful tool such as Titan at ORNL - to achieve these results."

While the distribution of electric charge inside the atomic nucleus is well known from experiments involving electron scattering, the distribution of the neutrons, which have no electric charge, is difficult to measure. In the nucleus of calcium-48, which has eight more neutrons than protons, the neutron distribution extends beyond the charge distribution and thereby sets the actual size of this nucleus. "This is the first really reliable calculation of such a massive nucleus from first principles", stated Gaute Hagen. "We reproduced basic observables for the first time by building this nucleus from scratch. We've answered a basic question - what is the size of the atomic nucleus?"

The ORNL-led team calculated radii, binding energies and dipole polarizabilities for helium-4, oxygen-16 and calcium-40 and accurately reproduced measurements of these isotopes. "That was a quality check of our calculation", Gaute Hagen stated. "It gives us confidence about our predictions for calcium-48."

The team, which included partners from the University of Tennessee, Michigan State University, Chalmers University of Technology, Sweden; TRIUMF, Canada; Hebrew University, Israel; Technical University Darmstadt, Germany; University of Oslo, Norway; and University of Trento, Italy, turned to Titan, a Cray XK7 system at Oak Ridge Leadership Computing Facility, a DOE Office of Science User facility at ORNL. The project ran the nuclear structure code NUCCOR - Nuclear Coupled Cluster at Oak Ridge, for about 15 million CPU hours, allocated through the Innovative and Novel Impact on Theory and Experiment programme.

Researchers at Jefferson Lab are preparing to measure the neutron radius of calcium-48. A team of physicists, the Darmstadt-Osaka Collaboration, has already measured its dipole polarizability and is analyzing the results. The findings could validate the work of Gaute Hagen's team and constrain future theoretical models.

The title of theNature Physicspaper is " Neutron and weak-charge distributions of the 48Ca nucleus ".

This research was also supported by the DOE Office of Science, in part through an Office of Science Early Career Research Programme Award to Gaute Hagen. In addition, the work used resources of the Jülich Supercomputing Center in Germany. Other support came from the U.S. National Science Foundation, the European Research Council, the United States-Israel Binational Science Foundation, and the governments of Canada, Italy, Norway and Sweden.
Source: DOE/Oak Ridge National Laboratory

Back to Table of contents

Primeur weekly 2015-11-09

Special

HARNESS explored principles to integrate heterogeneous resources into Cloud platform ...

Focus

Combining the benefits of both GPU and CPU in heterogeneous computing ...

Exascale supercomputing

Towards future supercomputing: EU project Exa2Green improves energy efficiency in high performance computing ...

DEEP project unveils next-generation HPC platform ...

Focus on Europe

Launch of BioExcel - Centre of Excellence for Biomolecular Research ...

Information security community for e-infrastructures crystalises at WISE workshop ...

ALCF helps tackle the Large Hadron Collider's Big Data challenge ...

Middleware

Bright Computing to release updates to popular management software at SC15 ...

Altair partners with South Africa's Centre for High Performance Computing ...

Cray, AMPLab, NERSC collaboration targets Spark performance on HPC platforms ...

Hardware

Singapore scientists among the first to benefit from Infinera Cloud Xpress with 100 GbE for data centre interconnect ...

Supermicro world record performance benchmarks for SYS-1028GR-TR with Intel Xeon Phi coprocessors announced at Fall 2015 STAC Summit ...

IBM Teams with Mellanox to help maximize performance of Power Systems LC line servers for Cloud and cluster deployments ...

LSU deploys new IBM supercomputer "Delta" to advance Big Data research in Louisiana ...

Applications

Nomadic computing speeds up Big Data analytics ...

Clemson researchers and IT scientists team up to tackle Big Data ...

Calcium-48's 'neutron skin' thinner than previously thought ...

Oklahoma University collaborating in NSF South Big Data Regional Innovation Hub ...

Columbia to lead Northeast Big Data Innovation Hub ...

University of Miami gets closer to helping find a cure for gastrointestinal cancer thanks to DDN storage ...

The Cloud

Cornell leads new National Science Foundation federated Cloud project ...

Bright Computing reveals plans for Cloud Expo Frankfurt ...

UberCloud delivers CAE Applications as a Service ...

IBM plans to acquire The Weather Company's product and technology businesses; extends power of Watson to the Internet of Things ...

Oracle updates Oracle Cloud Infrastructure services ...