翻訳と辞書
Words near each other
・ Griffith's experiment
・ Griffith's sign
・ Griffith's Valuation
・ Griffith, Australian Capital Territory
・ Griffith, Indiana
・ Griffith, New South Wales
・ Griffith, Virginia
・ Griffith-Merrillville Airport
・ Griffith-Sowers House
・ Griffiths
・ Griffiths Building (Toronto)
・ Griffiths Commission on Personal Debt
・ Griffiths Corner, Virginia
・ Griffiths Glacier
・ Griffiths group
Griffiths inequality
・ Griffiths Island
・ Griffiths Mxenge
・ Griffiths Stadium
・ Griffiths-Priday Ocean State Park
・ Griffiths-Scott Middle School
・ Griffithsin
・ Griffithstown
・ Griffithstown Railway Museum
・ Griffithsville, West Virginia
・ Griffithville School
・ Griffithville, Arkansas
・ Griffoens Geel
・ Griffon
・ Griffon (disambiguation)


Dictionary Lists
翻訳と辞書 辞書検索 [ 開発暫定版 ]
スポンサード リンク

Griffiths inequality : ウィキペディア英語版
Griffiths inequality
In statistical mechanics, the Griffiths inequality, sometimes also called Griffiths–Kelly–Sherman inequality or GKS inequality, named after Robert B. Griffiths, is a correlation inequality for ferromagnetic spin systems. Informally, it says that in ferromagnetic spin systems, if the 'a-priori distribution' of the spin is invariant under spin flipping, the correlation of any monomial of the spins is non-negative; and the two point correlation of two monomial of the spins is non-negative.
The inequality was proved by Griffiths for Ising ferromagnets with two-body interactions, then generalised by Kelly and Sherman to interactions involving an arbitrary number of spins, and then by Griffiths to systems with arbitrary spins. A more general formulation was given by Ginibre, and is now called the Ginibre inequality.
==Definitions==
Let \textstyle \sigma=\_ be a configuration of (continuous or discrete) spins on a lattice ''Λ''. If ''A'' ⊂ ''Λ'' is a list of lattice sites, possibly with duplicates, let \textstyle \sigma_A = \prod_ \sigma_j be the product of the spins in ''A''.
Assign an ''a-priori'' measure ''dμ(σ)'' on the spins;
let ''H'' be an energy functional of the form
:H(\sigma)=-\sum_ J_A \sigma_A ~,
where the sum is over lists of sites ''A'', and let
: Z=\int d\mu(\sigma) e^
be the partition function. As usual,
: \langle \cdot \rangle = \frac \sum_\sigma \cdot(\sigma) e^
stands for the ensemble average.
The system is called ''ferromagnetic'' if, for any list of sites ''A'', ''JA ≥ 0''. The system is called ''invariant under spin flipping'' if, for any ''j'' in ''Λ'', the measure ''μ'' is preserved under the sign flipping map ''σ → τ'', where
: \tau_k = \begin
\sigma_k, &k\neq j, \\
- \sigma_k, &k = j.
\end


抄文引用元・出典: フリー百科事典『 ウィキペディア(Wikipedia)
ウィキペディアで「Griffiths inequality」の詳細全文を読む



スポンサード リンク
翻訳と辞書 : 翻訳のためのインターネットリソース

Copyright(C) kotoba.ne.jp 1997-2016. All Rights Reserved.