Constructing soluble quantum spin models - Department of Physics ...
Constructing soluble quantum spin models - Department of Physics ...
Constructing soluble quantum spin models - Department of Physics ...
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H.Y. Shik et al. / Nuclear <strong>Physics</strong> B 666 [FS] (2003) 337–360 359<br />
K,M<br />
∑<br />
Hψ D =−2J 1<br />
k,m=1<br />
S k,m · S k,m ψ D<br />
K−1,M<br />
∑<br />
+ 2(2J 2 − J 3 − J 4 ) S k,m · S k+1,m ψ D<br />
k,m=1<br />
K,M−1<br />
∑<br />
+ 2(J 6 + J 7 − J 5 − J 8 ) S k,m · S k,m+1 ψ D .<br />
k,m=1<br />
(B.5)<br />
It is clear that the complete dimerized state ψ D is an eigenstate with eigenenergy<br />
E D =−2J 1 KMS(S + 1) when the conditions in Eq. (41) hold.<br />
For the three-dimensional model,<br />
K,L,M<br />
∑<br />
H 3D = 2J 1<br />
k,l,m=1<br />
S k,l,m · S k,l,m<br />
K−1,L−1,M<br />
∑<br />
+ 2(2J 2 − J 3 − J 4 ) (S k,l,m · S k+1,l,m + S k,l,m · S k,l+l,m )<br />
k,l,m=1<br />
K,L,M−1<br />
∑<br />
+ 2(2J 6 − J˜<br />
1 ) S k,l,m · S k,l,m+1<br />
+ 4 ( J ‖ 6 − J 7<br />
k,l,m=1<br />
) K−2,L−2,M ∑<br />
k,l,m=1<br />
(S k,l,m · S k+2,l,m + S k,l,m · S k,l+2,m )<br />
K−1,L−1,M−1<br />
∑<br />
+ 2(2J 8 − J˜<br />
3 )<br />
(S k,l,m+1 · S k+1,l,m + S k,l,m+1 · S k,l+1,m )<br />
k,l,m=1<br />
K−1,L−1,M−1<br />
∑<br />
+ 2(2J 8 − J˜<br />
4 )<br />
(S k,l,m · S k+1,l,m+1 + S k,l,m · S k,l+1,m+1 )<br />
k,l,m=1<br />
K−2,L−2,M−1<br />
∑<br />
+ 2(2J 11 − J˜<br />
7 )<br />
(S k,l,m · S k+2,l,m+1 + S k,l,m · S k,l+2,m+1<br />
k,l,m=1<br />
+ S k,l,m+1 · S k+2,l,m + S k,l,m+1 · S k,l+2,m )<br />
K−1,L−1,M−1<br />
∑<br />
+ 2(2J 9 − J˜<br />
5 )<br />
(S k,l,m · S k+1,l+1,m+1 + S k+1,l,m · S k,l+1,m+1<br />
+ 4J ‖ 7<br />
K−2,L−1,M<br />
∑<br />
k,l,m=1<br />
k,l,m=1<br />
+ S k,l+1,m · S k+1,l,m+1 + S k+1,l+1,m · S k,l,m+1 )<br />
(S k,l,m · S k+2,l+1,m + S k+2,l,m · S k,l+1,m )