May 31, 2017 Janus II FPGA modules. Credit: janus-computer.com/galery-janusII

The JANUS supercomputer has enabled researchers to reproduce the experimental protocol of equilibrium dynamics in spin glasses. The success of the simulation connects theoretical and experimental physical developments using this new generation of computers.

One common characteristic of certain systems such as polymers, supercooled liquids, colloids or spin glasses is that they take a long time to reach equilibrium. They are determined by very slow dynamics at low temperatures. The 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 are highly correlated.

Theoretical physicists can calculate this microscopic correlation length by simulating a large number of particles and following their individual behaviour in a supercomputer. These kinds of studies cannot be carried out experimentally because 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 that modify the energy barriers between the different states.

Thanks to the JANUS II supercomputer, researchers from Spain and Italy 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 us to directly connect theoretical developments to the experimental ones. We took spin glasses as a reference, because they are cleaner to study as a reference system," explains Juan Jess 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 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 Jess Ruz 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

Explore further: Revealing the fast atomic motion of network glasses with coherent X-rays

More information: M. Baity-Jesi et al, Matching Microscopic and Macroscopic Responses in Glasses, Physical Review Letters (2017). DOI: 10.1103/PhysRevLett.118.157202

Journal reference: Physical Review Letters

Provided by: University of Extremadura

The remarkable properties of glasses are due to their dynamical arrested state in which relaxations occur on time scales too large to be observed, or so it was believed. Now researchers have discovered the existence of unexpected ...

Janus was a Roman god with two distinct faces. Thousands of years later, he inspired material scientists working on asymmetrical microscopic sphereswith both a magnetic and a non-magnetic halfcalled Janus particles. ...

Cassini's narrow angle camera captures Saturn's tiny irregular moon Janus surrounded by the vast, dark expanse of the outer solar system.

Fermions are ubiquitous elementary particles. They span from electrons in metals, to protons and neutrons in nuclei and to quarks at the sub-nuclear level. Further, they possess an intrinsic degree of freedom called spin ...

Glasses are amorphous (non-crystalline) solids that are widely used in everyday life and in technological instruments. It is important to understand the behavior of materials that form glasses; that is, to study the dynamics ...

In physics, confinement of particles is such an important phenomenon that the Clay Mathematics Institute has even pledged an award of a million dollars to anyone who can give a convincing and exhaustive scientific explanation ...

(Phys.org)Decision-making is typically thought of as something done by intelligent living things and, in modern times, computers. But over the past several years, researchers have demonstrated that physical objects such ...

In response to popular demand, materials scientists at Duke University have resurrected an online cookbook of crystalline structures that started when the World Wide Web was Netscape Navigator and HTML 1.0.

The emerging field of plasmonics could bring advances in chemical manufacturing, usher in new clean and sustainable technologies and desalination systems to avert a future global water crisis.

(Phys.org)For the first time, researchers have demonstrated that shining a nanosecond pulsed laser at the base of a 100-m-long diamond needle can significantly enhance electron emission from the tip of the needle. The ...

(Phys.org)A large team of researchers with members from China, the U.K., the U.S. and Japan has developed a material that can switch between multiple phases with distinct electronic, optical and magnetic properties. In ...

A ripe apple falling from a tree has inspired Sir Isaac Newton to formulate a theory that describes the motion of objects subject to a force. Newton's equations of motion tell us that a moving body keeps on moving on a straight ...

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Visit link:

Researchers measure the coherence length in glasses using the supercomputer JANUS - Phys.Org