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Long-range forces and data compression in Vortex State simulations

Long-range forces and data compression in Vortex State simulations
Long-range forces and data compression in Vortex State simulations
We report on two aspects of simulations of the vortex state in high-temperature superconductors. Firstly, we cover the treatment of the involved long-range forces. Secondly, we suggest improvements on how to compress vortex position data effectively to enable visualisation of complex systems. A number of problems arise when long-range forces such as $K_1(x)$ or $1/x$ are used in particle-particle simulations. If a simple cut-off for the interaction is used, the system may find an equilibrium configuration at zero temperature that is not a regular lattice yet has an energy lower than the theoretically predicted minimum for the physical system: this is an artefact of the cut-off [1]. We have developed two methods to overcome these problems in Monte Carlo and molecular dynamics simulations. The first uses a smoothed potential to truncate the interaction in a single unit cell: this is appropriate for phenomenological characterisations, but may be applied to any potential. The second is a new method for the $K_0(x)$ potential and sums the energy in an infinitely tiled periodic system, which is in excess of 20,000 times faster than previous naive methods which add periodic images in shells of increasing radius: this is suitable for quantitative studies. Finally, we demonstrate how tree methods and space filling curves can be used to store particle data more efficiently. [1] H. Fangohr et. al., Peter A.J. de Groot and Geoffrey J. Daniell and Ken S. Thomas (2000) Efficient Methods for Handling Long-Range Forces in Particle-Particle Simulations. Journal of Computational Physics, 162 p.372-384.
Fangohr, Hans
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Cox, Simon
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Price, Andrew
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Daniell, Geoffrey J.
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Robinson, Alexa M.
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de Groot, P.A.J.
98c21141-cf90-4e5c-8f2b-d2aae8efb84d
Fangohr, Hans
9b7cfab9-d5dc-45dc-947c-2eba5c81a160
Cox, Simon
0e62aaed-24ad-4a74-b996-f606e40e5c55
Price, Andrew
f4db9dfc-23b6-4c11-8da6-bbf0ee35d6d5
Daniell, Geoffrey J.
82c59eea-5002-4889-8823-2c6e5b3288d3
Robinson, Alexa M.
7663e9a7-10d9-4ceb-9e1a-5369fcdaf29a
de Groot, P.A.J.
98c21141-cf90-4e5c-8f2b-d2aae8efb84d

Fangohr, Hans, Cox, Simon, Price, Andrew, Daniell, Geoffrey J., Robinson, Alexa M. and de Groot, P.A.J. (2000) Long-range forces and data compression in Vortex State simulations.

Record type: Other

Abstract

We report on two aspects of simulations of the vortex state in high-temperature superconductors. Firstly, we cover the treatment of the involved long-range forces. Secondly, we suggest improvements on how to compress vortex position data effectively to enable visualisation of complex systems. A number of problems arise when long-range forces such as $K_1(x)$ or $1/x$ are used in particle-particle simulations. If a simple cut-off for the interaction is used, the system may find an equilibrium configuration at zero temperature that is not a regular lattice yet has an energy lower than the theoretically predicted minimum for the physical system: this is an artefact of the cut-off [1]. We have developed two methods to overcome these problems in Monte Carlo and molecular dynamics simulations. The first uses a smoothed potential to truncate the interaction in a single unit cell: this is appropriate for phenomenological characterisations, but may be applied to any potential. The second is a new method for the $K_0(x)$ potential and sums the energy in an infinitely tiled periodic system, which is in excess of 20,000 times faster than previous naive methods which add periodic images in shells of increasing radius: this is suitable for quantitative studies. Finally, we demonstrate how tree methods and space filling curves can be used to store particle data more efficiently. [1] H. Fangohr et. al., Peter A.J. de Groot and Geoffrey J. Daniell and Ken S. Thomas (2000) Efficient Methods for Handling Long-Range Forces in Particle-Particle Simulations. Journal of Computational Physics, 162 p.372-384.

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More information

Published date: December 2000
Additional Information: Poster Presentation, Condensed Matter and Materials Physics Conference, Bristol, United Kingdom.
Organisations: Electronics & Computer Science

Identifiers

Local EPrints ID: 256010
URI: http://eprints.soton.ac.uk/id/eprint/256010
PURE UUID: 2a8c235b-0156-47f6-901c-cfd98ffd6523
ORCID for Hans Fangohr: ORCID iD orcid.org/0000-0001-5494-7193

Catalogue record

Date deposited: 26 Aug 2001
Last modified: 21 Nov 2019 01:37

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