{ "id": "2005.04393", "version": "v1", "published": "2020-05-09T08:34:40.000Z", "updated": "2020-05-09T08:34:40.000Z", "title": "Combinatorics for calculating expectations of stochastic differential equations", "authors": [ "Jun Ohkubo" ], "comment": "16 pages, 5 figures", "categories": [ "cond-mat.stat-mech" ], "abstract": "Combinatorial discussion is proposed and applied for calculating expectations of stochastic differential equations. Starting from the duality theory of stochastic processes, some modifications of interpretation and usages of time-ordering operators naturally lead to combinatorial discussions. As a demonstration, the first and second moments for the Ornstein-Uhlenbeck process are re-derived from the combinatorial discussion. Furthermore, two numerical methods for practical applications are proposed. One is based on a conventional exponential expansion and the Pade approximation. Another uses a resolvent of a time-evolution operator, and the Aitken series acceleration method is also employed. These two proposals recover the correct results approximately.", "revisions": [ { "version": "v1", "updated": "2020-05-09T08:34:40.000Z" } ], "analyses": { "keywords": [ "stochastic differential equations", "calculating expectations", "combinatorial discussion", "combinatorics", "aitken series acceleration method" ], "note": { "typesetting": "TeX", "pages": 16, "language": "en", "license": "arXiv", "status": "editable" } } }