Researchers measure the coherence length in glasses using the supercomputer JANUS

May 30, 2017

The use of the JANUS supercomputer has enabled researchers to reproduce the experimental protocol of equilibrium dynamics in spin glasses. The success of the simulation enables us to connect theoretical physical developments with experimental ones, using this new generation of computers.

One common characteristic of certain systems such as polymers, supercooled liquids, colloids or spin glasses is that they require very long times to reach equilibrium. They are determined by very slow dynamics at low temperatures. Actually, their dynamic is so slow that thermal equilibrium is never attained in macroscopic samples. This type of dynamic is characterised by a correlation or coherence length that indicates that particles situated at a shorter distance than this length are very correlated.

Theoretical physicists can calculate this (microscopic) correlation length by simulating a large number of particles and following the individual behaviour of all the particles in a supercomputer. These kinds of studies cannot be carried out experimentally (it is impossible to track all the particles of a system), but it is possible to calculate a (macroscopic) correlation length by applying external fields on the system which modify the energy barriers between the different states.

Thanks to the JANUS II supercomputer, researchers from Spain and Italy (Institute of Biocomputation and Physics of Complex Systems (BIFI) of the University of Zaragoza, Complutense University of Madrid, University of Extremadura, La Sapienza University of Rome and University of Ferrara), have refined the calculation of the microscopic correlation length and have reproduced the experimental protocol, enabling them to calculate the macroscopic length. The success of the simulation confirmed that both microscopic and experimental (macroscopic) length are equal.

"This study provides a theoretical basis for studies in these physical systems and the results obtained allow one to directly connect the theoretical developments to the experimental ones. We did the research taking as a reference spin glasses, because they are cleaner to study as a reference system", explains Juan Jesús Ruiz Lorenzo, a theoretical physicist at the UEx and one of the authors of this study which has been published in the magazine Physical Review Letters.

JANUS computer

The JANUS II computer is a new generation of supercomputer located in the BIFI (Institute of Biocomputation and Physics of Complex Systems). "Thanks to this 'dedicated' computer, we are able to simulate one second of the experiment, within the range of the experimental times", says Juan Jesús Ruíz Lorenzo. JANUS II is a dedicated supercomputer based on reconfigurable FPGA processors.

The researchers have reproduced a landmark experiment on the Janus I and Janus II supercomputers that measures the coherence length in spin glasses. The coherence (correlation) length value estimated through analysis of microscopic correlation functions is quantitatively consistent with its measurements via macroscopic response functions
-end-


University of Extremadura

Related Supercomputer Articles from Brightsurf:

Supercomputer reveals atmospheric impact of gigantic planetary collisions
The giant impacts that dominate late stages of planet formation have a wide range of consequences for young planets and their atmospheres, according to new research.

Supercomputer model simulations reveal cause of Neanderthal extinction
IBS climate scientists discover that according to new supercomputer model simulations, only competition between Neanderthals and Homo sapiens can explain the rapid demise of Neanderthals around 43 to 38 thousand years ago.

Supercomputer simulations present potential active substances against coronavirus
Several drugs approved for treating hepatitis C viral infection were identified as potential candidates against COVID-19, a new disease caused by the SARS-CoV-2 coronavirus.

Coronavirus massive simulations completed on Frontera supercomputer
Coronavirus envelope all-atom computer model being developed by Amaro Lab of UC San Diego on NSF-funded Frontera supercomputer of TACC at UT Austin.

Supercomputer shows 'Chameleon Theory' could change how we think about gravity
Supercomputer simulations of galaxies have shown that Einstein's theory of General Relativity might not be the only way to explain how gravity works or how galaxies form.

Scientists develop way to perform supercomputer simulations of the heart on cellphones
You can now perform supercomputer simulations of the heart's electrophysiology in real time on desktop computers and even cellphones.

Tianhe-2 supercomputer works out the criterion for quantum supremacy
A world's first criterion for quantum supremacy was issued, in a research jointly led by Prof.

Supercomputer simulations show new target in HIV-1 replication
Nature study found naturally-occurring compound inositol hexakisphosphate (IP6) promotes both assembly and maturation of HIV-1.

Researchers measure the coherence length in glasses using the supercomputer JANUS
Thanks to the JANUS II supercomputer, researchers from Spain and Italy (Institute of Biocomputation and Physics of Complex Systems of the University of Zaragoza, Complutense University of Madrid, University of Extremadura, La Sapienza University of Rome and University of Ferrara), have refined the calculation of the microscopic correlation length and have reproduced the experimental protocol, enabling them to calculate the macroscopic length.

Officials dedicate OSC's newest, most powerful supercomputer
State officials and Ohio Supercomputer Center leaders gathered at a data center today (March 29) to dedicate the Owens Cluster.

Read More: Supercomputer News and Supercomputer Current Events
Brightsurf.com is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to Amazon.com.