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arXiv 1807.07884math-phmath.MP
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Baker-Campbell-Hausdorff公式的精确幂级数表示

An exact power series representation of the Baker-Campbell-Hausdorff formula

Jordan C. Moodie, Martin W. Long

摘要:

构造了Baker-Campbell-Hausdorff公式在两个变量之一上的幂级数的精确表示。这个系列的封闭形式的系数被发现在双曲函数,其中包含所有的第二个变量的依赖。有人认为,这个确切的系列,然后可以被截断,并预计给一个很好的近似充分的扩展,如果只有微扰变量是小的。这改进了现有的公式,现有的公式要求两者都很小。因此,这可以允许在采用贝克-坎贝尔-豪斯多夫公式的物理问题中访问更大的相空间,同时使新的问题能够得到解决。

英文摘要:

An exact representation of the Baker-Campbell-Hausdorff formula as a power series in just one of the two variables is constructed. Closed form coefficients of this series are found in terms of hyperbolic functions, which contain all of the dependence of the second variable. It is argued that this exact series may then be truncated and expected to give a good approximation to the full expansion if only the perturbative variable is small. This improves upon existing formulae, which require both to be small. As such this may allow access to larger phase spaces in physical problems which employ the Baker-Campbell-Hausdorff formula, along with enabling new problems to be tackled.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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