有效经典配分函数的变分微扰近似及统计涨落修正

Variational Perturbation Approach to the Effective Classical Partition Function and Statistical Correction

应用变分微扰近似求得试探系统的有效经典配分函数和有效经典势 考虑极值条件〈A-A0 〉0 =0 ,给出了自由能最佳上界和最佳配分函数 在此基础上 ,进一步研究了二阶统计涨落〈(A -A0 ) 2 -〈A -A0 〉20 〉0 ,以及自由能F和有效经典势的二阶修正 结果说明 。

Variational perturbation approach is applied to obtain the effective classical partition function and the effective classical potential of the trial system.Under the minization condition 〈A-A 0〉 0=0,the optimal upper bound F 0 and the optimal partition function have been given.On this basis,the second-order statistical fluctuation 〈(A-A 0) 2-〈A-A 0〉 2 0〉 0,and the second-order correction for the free energy F and the effective classical potential are also investigated. It is shown that this correction is important in the low temperature.