On the interpretations of Langevin stochastic equation in different coordinate systems
✍ Scribed by E. Martı́nez; L. López-Dı́az; L. Torres; O. Alejos
- Publisher
- Elsevier Science
- Year
- 2004
- Tongue
- English
- Weight
- 114 KB
- Volume
- 343
- Category
- Article
- ISSN
- 0921-4526
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✦ Synopsis
The stochastic Langevin Landau-Lifshitz equation is usually utilized in micromagnetics formalism to account for thermal effects. Commonly, two different interpretations of the stochastic integrals can be made: Ito and Stratonovich. In this work, the Langevin-Landau-Lifshitz (LLL) equation is written in both Cartesian and Spherical coordinates. If Spherical coordinates are employed, the noise is additive, and therefore, Ito and Stratonovich solutions are equal. This is not the case when (LLL) equation is written in Cartesian coordinates. In this case, the Langevin equation must be interpreted in the Stratonovich sense in order to reproduce correct statistical results.
Nevertheless, the statistics of the numerical results obtained from Euler-Ito and Euler-Stratonovich schemes are equivalent due to the additional numerical constraint imposed in Cartesian system after each time step, which itself assures that the magnitude of the magnetization is preserved.
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