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arXiv 0711.3989hep-thcond-mat.stat-mechquant-ph
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无图扰动结果

Perturbative Results Without Diagrams

R. Rosenfelder

摘要:

量子(场)理论中的高阶微扰计算受到单个图数量的阶乘增加的影响。在这里,我描述了一种方法,它评估的总贡献数值有限的温度从累积膨胀相应的观察,然后外推到零温度。这种方法(最初由Bogolyubov和Plechko提出)被应用于计算极化子基态能量的高阶项。使用最先进的多维积分例程,获得对应于4-和5-循环计算的2个新系数。

英文摘要:

Higher-order perturbative calculations in Quantum (Field) Theory suffer from the factorial increase of the number of individual diagrams. Here I describe an approach which evaluates the total contribution numerically for finite temperature from the cumulant expansion of the corresponding observable followed by an extrapolation to zero temperature. This method (originally proposed by Bogolyubov and Plechko) is applied to the calculation of higher-order terms for the ground-state energy of the polaron. Using state-of-the-art multidimensional integration routines 2 new coefficients are obtained corresponding to a 4- and 5-loop calculation.

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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