The molecular field approximation


by matematikuvol
Tags: approximation, field, molecular
matematikuvol
matematikuvol is offline
#1
Oct9-11, 04:10 PM
P: 192
MFA

[tex]\hat{A}\hat{B}\approx \hat{A}\langle\hat{B}\rangle+\hat{B}\langle\hat{A}\rangle-\langle\hat{A}\rangle\langle\hat{B}\rangle[/tex]

What this mean physically? What we neglect here?

If I calculate Neel temperature using this method [tex]T_N^{MFA}[/tex] and using RPA method [tex]T_N^{RPA}[/tex] is there some relation between those temperatures?
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xiyangxixia
xiyangxixia is offline
#2
Oct9-11, 10:55 PM
P: 6
mean-field approximation method
genneth
genneth is offline
#3
Oct10-11, 08:06 AM
P: 981
Perhaps a natural way to see the decomposition is if A and B are fluctuations around some mean, i.e. <A> = <B> = 0. Then you just have AB ~ 0, i.e. you are neglecting correlated fluctuations in A and B.


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