Addition of the spin angular momentum of three (four...

30
1 Addition of the spin angular momentum of three (four) electrons with S = 1/2 Masatsugu Suzuki Department of Physics, SUNY at Binghamton (Date: October 23, 2013) Here we show how to derive the eigenvalues and eigenkets of 2 ˆ S , the spin states of the three and four electrons with spin 1/2, where S ˆ is the total spin angular momentum defined by 3 2 1 ˆ ˆ ˆ ˆ S S S S , for the three particles 4 3 2 1 ˆ ˆ ˆ ˆ ˆ S S S S S . for the four particles There are two methods. One is the conventional method to use the Clebsch-Gordan coefficients for the addition of spin angular momentum. Using the program of ClebschGordan (Mathematica), we can derive the expression for the eigenket and eigenvalues for 2 ˆ S for the many spin particles. The second method is to use the KroneckerProduct of the Mathematica for both the three and four spins. We calculate the expression of the matrix for 2 ˆ S ; 8x8 matrix for the three spin particles and 16x16 matrix for the four spin particles. Using the Mathematica we solve the eigenvalue problems to get the eigenvalues and eigenkets for each case. We can also solve the eigenvalue problem even for the five spin particles, the 32x32 martix by using the Mathematica. Note that for the n particle systems, we need to solve the eigenvalue problem for 2 n x2 n martix (n = 2, 3, 4, 5, 6, ...). 1. States of three particles with spin 1/2 (I) We can regard three electrons as 2+1 electrons, in the sense that we can combine an electron (s = 1/2) with the triplet two-electron state (s = 1) and with the singlet two-electron state (s = 0). 0 1 2 / 1 2 / 1 D D D D . ((Case-1)) 2 / 1 2 / 1 2 / 3 2 / 1 0 2 / 1 1 2 / 1 0 1 2 / 1 2 / 1 2 / 1 2 / 1 2 / 1 2 / 1 ) ( ) ( D D D D D D D D D D D D D D D D In the case of ) ( 2 / 1 2 / 3 D D , the results on the addition of the angular momenta shows that we should get two groups of three-electron spin states corresponding to S = 3/2 and S = 1/2. In the

Transcript of Addition of the spin angular momentum of three (four...

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Addition of the spin angular momentum of three (four) electrons with S = 1/2 Masatsugu Suzuki

Department of Physics, SUNY at Binghamton (Date: October 23, 2013)

Here we show how to derive the eigenvalues and eigenkets of 2S , the spin states of the three and

four electrons with spin 1/2, where S is the total spin angular momentum defined by

321ˆˆˆˆ SSSS , for the three particles

4321ˆˆˆˆˆ SSSSS . for the four particles

There are two methods. One is the conventional method to use the Clebsch-Gordan coefficients for the addition of spin angular momentum. Using the program of ClebschGordan (Mathematica),

we can derive the expression for the eigenket and eigenvalues for 2S for the many spin particles. The second method is to use the KroneckerProduct of the Mathematica for both the three and

four spins. We calculate the expression of the matrix for 2S ; 8x8 matrix for the three spin particles and 16x16 matrix for the four spin particles. Using the Mathematica we solve the eigenvalue problems to get the eigenvalues and eigenkets for each case. We can also solve the eigenvalue problem even for the five spin particles, the 32x32 martix by using the Mathematica.

Note that for the n particle systems, we need to solve the eigenvalue problem for 2nx2n martix (n = 2, 3, 4, 5, 6, ...). 1. States of three particles with spin 1/2 (I)

We can regard three electrons as 2+1 electrons, in the sense that we can combine an electron (s = 1/2) with the triplet two-electron state (s = 1) and with the singlet two-electron state (s = 0).

012/12/1 DDDD .

((Case-1))

2/12/12/3

2/102/11

2/101

2/12/12/12/12/12/1

)(

)(

DDD

DDDD

DDD

DDDDDD

In the case of )( 2/12/3 DD , the results on the addition of the angular momenta shows that we

should get two groups of three-electron spin states corresponding to S = 3/2 and S = 1/2. In the

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second case we get a single group that corresponds to S = 1/2. We thus expect one quartet group of spin states (S = 3/2) and two distinct doublet groups of spin states (S = 1/2), or a total of 4+2+2 = 8 individual three-electron spin states. (1) j = 3/2.

)3()2()1(2

3,

2

3 ,

3

)3()2()1()3()2()1()3()2()1(

2

1,

2

3

3

)3()2()1()3()2()1()3()2()1(

2

1,

2

3

)3()2()1(2

3,

2

3

___________________________________________________________________________ (ii) j = 1/2.

6

)3()2()1(2)3()2()1()3()2()1(

2

1,

2

1

6

)3()2()1()3()2()1(2)3()2()1(

2

1,

2

1

_____________________________________________________________________________ (iii) j = 1/2

2

)3()2()1()3()2()1(

2

1,

2

1

2

)3()2()1()3()2()1(

2

1,

2

1

Note that and denote the upper spin state and the lower spin state, respectively;

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3

0

1z ,

0

1z

The numbers 1, 2, and 3 are the sites of spins. These results are the same as those derived by Tomonaga, except for the sign. ((Mathematica-1))

Clear"Global`"; CCGGj1_, m1_, j2_, m2_, j_, m_ :

Modules1,

s1 IfAbsm1 b j1 && Absm2 b j2 && Absm b j,

ClebschGordanj1, m1, j2, m2, j, m, 0;

CG2j1_, j2_, j_, a1_, a2_ :

TableSumCCGGj1, k1, j2, k2, j, k1 k2 a1j1, k1 a2j2, k2KroneckerDeltak1 k2, m, k1, j1, j1, k2, j2, j2, m, j, j

j1=1/2, j2=1/2 j = 1, 0

CG212, 12, 1, b1, b2 TableForm

b1 12

, 12 b2 1

2, 1

2

b112

, 12 b2 1

2, 1

2

2

b112

, 12 b2 1

2, 1

2

2

b1 12

, 12 b2 1

2, 1

2

CG212, 12, 0, b1, b2 TableForm

b112

, 12 b2 1

2, 1

2

2

b112

, 12 b2 1

2, 1

2

2j1=1, j2=1/2 j = 3/2

j1 1; j2 12; j 32;

TableSumCCGGj1, k1, j2, k2, j, k1 k2 CG212, 12, j1, b1, b2k1 j1 1b3j2, k2 KroneckerDeltak1 k2, m, k1, j1, j1, k2, j2, j2, m, j, j

Simplify

b11

2,

1

2 b21

2,

1

2 b31

2,

1

2,

b1 12

, 12 b2 1

2, 1

2 b3 1

2, 1

2 b1 1

2, 1

2 b2 1

2, 1

2 b3 1

2, 1

2 b2 1

2, 1

2 b3 1

2, 1

2

3,

b1 12

, 12 b2 1

2, 1

2 b3 1

2, 1

2 b1 1

2, 1

2 b2 1

2, 1

2 b3 1

2, 1

2 b2 1

2, 1

2 b3 1

2, 1

2

3,

b11

2,

1

2 b2 1

2,

1

2 b3 1

2,

1

2

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2. States of three particles with spin 1/2 (II)

We consider the second case. The results on the spin states are the same as those described in the textbook of Schiff.

2/12/12/3

02/112/1

012/1

2/12/12/12/12/12/1

)(

)(

DDD

DDDD

DDD

DDDDDD

(1) j = 3/2.

)3()2()1(2

3,

2

3 ,

3

)3()2()1()3()2()1()3()2()1(

2

1,

2

3 ,

3

)3()2()1()3()2()1()3()2()1(

2

1,

2

3 ,

j1=1, j2=1/2 j = 1/2

j1 1; j2 12; j 12;

TableSumCCGGj1, k1, j2, k2, j, k1 k2 CG212, 12, j1, b1, b2k1 j1 1b3j2, k2 KroneckerDeltak1 k2, m, k1, j1, j1, k2, j2, j2, m, j, j

Simplify

b1 1

2, 1

2 b2 1

2, 1

2 b3 1

2, 1

2 b1 1

2, 1

2 b2 1

2, 1

2 b3 1

2, 1

2 2 b2 1

2, 1

2 b3 1

2, 1

2

6,

b1 12

, 12 b2 1

2, 1

2 b3 1

2, 1

2 b1 1

2, 1

2 2 b2 1

2, 1

2 b3 1

2, 1

2 b2 1

2, 1

2 b3 1

2, 1

2

6

j1=0, j2=1/2 j = 1/2

j1 0; j2 12; j 12;

TableSumCCGGj1, k1, j2, k2, j, k1 k2 CG212, 12, j1, b1, b2k1 j1 1b3j2, k2 KroneckerDeltak1 k2, m, k1, j1, j1, k2, j2, j2, m, j, j

Simplify

b1 1

2, 1

2 b2 1

2, 1

2 b1 1

2, 1

2 b2 1

2, 1

2 b3 1

2, 1

2

2,

b1 12

, 12 b2 1

2, 1

2 b1 1

2, 1

2 b2 1

2, 1

2 b3 1

2, 1

2

2

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)3()2()1(2

3,

2

3 .

___________________________________________________________________________ (ii) j = 1/2.

6

)3()2()1()3()2()1()3()2()1(2

2

1,

2

1 ,

6

)3()2()1()3()2()1()3()2()1(2

2

1,

2

1 .

_____________________________________________________________________________ (iii) j = 1/2

2

)3()2()1()3()2()1(

2

1,

2

1 ,

2

)3()2()1()3()2()1(

2

1,

2

1 .

((Mathematica-2))

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Clear"Global`"; CCGGj1_, m1_, j2_, m2_, j_, m_ :

Modules1,

s1 IfAbsm1 b j1 && Absm2 b j2 && Absm b j,

ClebschGordanj1, m1, j2, m2, j, m, 0;

CG2j1_, j2_, j_, a1_, a2_ :

TableSumCCGGj1, k1, j2, k2, j, k1 k2 a1j1, k1 a2j2, k2KroneckerDeltak1 k2, m, k1, j1, j1, k2, j2, j2, m, j, j

j1=1/2, j2=1/2 j = 1, 0

CG212, 12, 1, b1, b2 TableForm

b1 12

, 12 b2 1

2, 1

2

b112

, 12 b2 1

2, 1

2

2

b112

, 12 b2 1

2, 1

2

2

b1 12

, 12 b2 1

2, 1

2

CG212, 12, 0, b1, b2 TableForm

b112

, 12 b2 1

2, 1

2

2

b112

, 12 b2 1

2, 1

2

2j1=1, j2=1/2 j = 3/2

j1 1; j2 12; j 32;

TableSumb1j2, k2 CCGGj1, k1, j2, k2, j, k1 k2CG212, 12, j1, b2, b3k1 j1 1 KroneckerDeltak1 k2, m,

k1, j1, j1, k2, j2, j2, m, j, j Simplify

b11

2,

1

2 b21

2,

1

2 b31

2,

1

2,

b1 12

, 12 b2 1

2, 1

2 b3 1

2, 1

2 b1 1

2, 1

2 b2 1

2, 1

2 b3 1

2, 1

2 b2 1

2, 1

2 b3 1

2, 1

2

3,

b1 12

, 12 b2 1

2, 1

2 b3 1

2, 1

2 b1 1

2, 1

2 b2 1

2, 1

2 b3 1

2, 1

2 b2 1

2, 1

2 b3 1

2, 1

2

3,

b11

2,

1

2 b2 1

2,

1

2 b3 1

2,

1

2

j1=1, j2=1/2 j = 1/2

j1 1; j2 12; j 12;

TableSumb1j2, k2 CCGGj1, k1, j2, k2, j, k1 k2CG212, 12, j1, b2, b3k1 j1 1 KroneckerDeltak1 k2, m,

k1, j1, j1, k2, j2, j2, m, j, j Simplify

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3. The three spin states (by the use of KroneckerProduct)

The magnitude of the total spin angular momentum:

)ˆˆˆˆˆˆ(2

14

9

)ˆˆ2ˆˆ2ˆˆ2ˆˆˆ(4

)ˆˆˆ(4

ˆ

133221

22

1332212

32

22

1

2

2321

22

σσσσσσ

σσσσσσσσσ

σσσS

and the z-component of the total spin angular momentum:

)ˆˆˆ(2

ˆ221 zzzzS

.

Using thr Kronecker product, the above operators can be rewritten as

)ˆˆ1ˆˆ1ˆˆ1

ˆ1ˆˆ1ˆˆ1ˆ

1ˆˆ1ˆˆ1ˆˆ(2

1114

9ˆ22

2

zzyyxx

zzyyxx

zzyyxx

S

)ˆ111ˆ111ˆ(2

ˆzzzzS

.

2 b1 1

2, 1

2 b2 1

2, 1

2 b3 1

2, 1

2 b1 1

2, 1

2 b2 1

2, 1

2 b3 1

2, 1

2 b2 1

2, 1

2 b3 1

2, 1

2

6,

2 b1 12

, 12 b2 1

2, 1

2 b3 1

2, 1

2 b1 1

2, 1

2 b2 1

2, 1

2 b3 1

2, 1

2 b2 1

2, 1

2 b3 1

2, 1

2

6

j1=0, j2=1/2 j = 1/2

j1 0; j2 12; j 12;

TableSumb1j2, k2 CCGGj1, k1, j2, k2, j, k1 k2CG212, 12, j1, b2, b3k1 j1 1 KroneckerDeltak1 k2, m,

k1, j1, j1, k2, j2, j2, m, j, j Simplify

b1 1

2, 1

2 b2 1

2, 1

2 b3 1

2, 1

2 b2 1

2, 1

2 b3 1

2, 1

2

2,

b1 12

, 12 b2 1

2, 1

2 b3 1

2, 1

2 b2 1

2, 1

2 b3 1

2, 1

2

2

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The matrix of 2S is obtained with the use of KrocknerProduct in the Mathematica, as

The matrix of zS is obtained as

Note that zS is the block-diagonnal matrix,but 2S is a non-diagonal matrix.

The eigenvalue problem of 2S . We use the Eigensystem (Mathematica) to solve the eigenvalue problem. The result is as follows: {eigenvalues, eigenkets}}

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The eigenkets of 2S (a)

0

0

0

0

0

0

0

1

2

3,

3

2mj ,

0

0

03

103

13

10

2

1,

2

3mj

03

13

103

10

0

0

2

1,

2

3mj ,

1

0

0

0

0

0

0

0

2

3,

2

3mj ,

(b) j = 1/2

154

,154

,154

,154

,34

,34

,34

,34,

0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 1, 0, 1, 1, 0, 0, 1, 1, 0, 1, 0, 0, 0,

1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 1, 0, 0, 0, 0, 1, 0, 1, 0, 0,

0, 1, 0, 0, 1, 0, 0, 0, 0, 1, 1, 0, 0, 0, 0, 0

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02

10

02

10

0

0

2

1,

2

1mj ,

0

0

02

10

02

10

2

1,

2

1mj

(c) j = 1/2

0

0

06

10

6

26

10

2

1,

2

1mj ,

06

16

206

10

0

0

2

1,

2

1mj

4. The four-spin states (by the use of KroneckerProduct) We now consider the eigenstates and eigenvalues for the four-spin system.

012

011012

00100111

0101

2/12/12/12/12/12/12/12/1

23

)(

)()(

)()(

DDD

DDDDDD

DDDDDDDD

DDDD

DDDDDDDD

The total states are 16 states (= 5 + 3 x 3+2), since

j = 2 m = 2, 1, 0, -1, -2 (one) 1 x 5 = 5 j = 1 m = 1, 0, -1 (three) 3 x 3 = 9 j = 0 m = 0. (two) 2 x 2 = 4

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The square of the magnitude of the total spin angular momentum

)ˆˆˆˆˆˆ

ˆˆˆˆˆˆ(2

13

)ˆˆ2ˆˆ2ˆˆ2

ˆˆ2ˆˆ2ˆˆ2ˆˆˆˆ(4

)ˆˆˆˆ(4

ˆ

434241

323121

22

434241

3231212

42

32

22

1

2

24321

22

σσσσσσ

σσσσσσ

σσσσσσ

σσσσσσσσσσ

σσσσS

The z component of the spin angular momentum:

)ˆˆˆˆ(2

ˆ4321 zzzzzS

These operators can be rewritten as

)ˆˆ11ˆˆ11ˆˆ11

ˆ1ˆ1ˆ1ˆ1ˆ1ˆ1

ˆ11ˆˆ11ˆˆ11ˆ

1ˆˆ11ˆˆ11ˆˆ1

1ˆ1ˆ1ˆ1ˆ1ˆ1ˆ

11ˆˆ11ˆˆ11ˆˆ(2

11113ˆ2

22

zzyyxx

zzyyxx

zzyyxx

zzyyxx

zzyyxx

zzyyxx

S

and

)ˆ111ˆ111ˆ(2

ˆzzzzS

Using the Mathematica we can solve the eigenvalue problems for the four spin 1/2 systems. The

matrix of 2S (16 x 16 matrix) is expressed by

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The matrix of zS (16 x 16 matrix) is expressed as

The eigenvalue problem of 2S (a) j = 2

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0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

1

2,2 mj

,

0

0

0

0

0

0

0

2/1

0

0

0

2/1

0

2/1

2/1

0

1,2 mj

0

0

0

6/1

0

6/1

6/1

0

0

6/1

6/1

0

6/1

0

0

0

0,2 mj

0

2/1

2/1

0

2/1

0

0

0

2/1

0

0

0

0

0

0

0

1,2 mj

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1

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

2,2 mj

_____________________________________________________________________________ (b)

0

0

0

0

0

0

0

2/1

0

0

0

0

0

0

2/1

0

1,1 mj

0

0

0

0

0

0

0

6/1

0

0

0

6/2

0

0

6/1

0

1,1 mj

0

0

0

0

0

0

0

6/3

0

0

0

6/3

0

2/3

6/3

0

1,1 mj

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0

0

0

2/1

0

0

0

0

0

0

0

0

2/1

0

0

0

0,1 mj

,

0

0

0

0

0

2/1

0

0

0

0

2/1

0

0

0

0

0

0,1 mj

0

0

0

0

0

0

2/1

0

0

2/1

0

0

0

0

0

0

0,1 mj

0

2/1

0

0

0

0

0

0

2/1

0

0

0

0

0

0

0

1,1 mj

0

6/1

6/2

0

0

0

0

0

6/1

0

0

0

0

0

0

0

1,1 mj

0

6/3

6/3

0

2/3

0

0

0

6/3

0

0

0

0

0

0

0

1,1 mj

______________________________________________________________________________

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0

0

0

2/1

0

0

2/1

0

0

2/1

0

0

2/1

0

0

0

0,0 mj

___________________________________________________________________________ (

0

0

0

6/3

0

3/1

6/3

0

0

6/3

3/1

0

6/3

0

0

0

0,0 mj

____________________________________________________________________________

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((Mathematica))

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Clear"Global`";

exp_ : exp . Complexre_, im_ Complexre, im; x 0 11 0

;

y 0 0

; z 1 00 1

;

I2 IdentityMatrix2;

ST1 1

2KroneckerProductx, x, I2, I2 KroneckerProducty, y, I2, I2 KroneckerProductz, z, I2, I2 KroneckerProductx, I2, x, I2 KroneckerProducty, I2, y, I2 KroneckerProductz, I2, z, I2 KroneckerProductx, I2, I2, x KroneckerProducty, I2, I2, y KroneckerProductz, I2, I2, z KroneckerProductI2, x, x, I2 KroneckerProductI2, y, y, I2 KroneckerProductI2, z, z, I2 KroneckerProductI2, I2, x, x KroneckerProductI2, I2, y, y KroneckerProductI2, I2, z, z KroneckerProductI2, x, I2, x KroneckerProduct I2, y, I2, y KroneckerProductI2, z, I2, z

3 KroneckerProductI2, I2, I2, I2;

ST1 MatrixForm

6 0 0 0 0 0 0 0 0 0 0 0 0 0 0 00 3 1 0 1 0 0 0 1 0 0 0 0 0 0 00 1 3 0 1 0 0 0 1 0 0 0 0 0 0 00 0 0 2 0 1 1 0 0 1 1 0 0 0 0 00 1 1 0 3 0 0 0 1 0 0 0 0 0 0 00 0 0 1 0 2 1 0 0 1 0 0 1 0 0 00 0 0 1 0 1 2 0 0 0 1 0 1 0 0 00 0 0 0 0 0 0 3 0 0 0 1 0 1 1 00 1 1 0 1 0 0 0 3 0 0 0 0 0 0 00 0 0 1 0 1 0 0 0 2 1 0 1 0 0 00 0 0 1 0 0 1 0 0 1 2 0 1 0 0 00 0 0 0 0 0 0 1 0 0 0 3 0 1 1 00 0 0 0 0 1 1 0 0 1 1 0 2 0 0 00 0 0 0 0 0 0 1 0 0 0 1 0 3 1 00 0 0 0 0 0 0 1 0 0 0 1 0 1 3 00 0 0 0 0 0 0 0 0 0 0 0 0 0 0 6

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eq1 EigensystemST1 Simplify

6, 6, 6, 6, 6, 2, 2, 2, 2, 2, 2, 2, 2, 2, 0, 0,

0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1,

0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 1, 0, 1, 1, 0,

0, 0, 0, 1, 0, 1, 1, 0, 0, 1, 1, 0, 1, 0, 0, 0,

0, 1, 1, 0, 1, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0,

1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,

0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 1, 0,

0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 1, 0, 0,

0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0,

0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0, 0,

0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0,

0, 0, 0, 0, 0, 0, 1, 0, 0, 1, 0, 0, 0, 0, 0, 0,

0, 1, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0,

0, 1, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,

0, 1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,

0, 0, 0, 1, 0, 0, 1, 0, 0, 1, 0, 0, 1, 0, 0, 0,

0, 0, 0, 0, 0, 1, 1, 0, 0, 1, 1, 0, 0, 0, 0, 0

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1 eq12, 1; 2 eq12, 2; 3 eq12, 3; 4 eq12, 4;

5 eq12, 5; 6 eq12, 6; 7 eq12, 7; 8 eq12, 8;

9 eq12, 9; 10 eq12, 10; 11 eq12, 11; 12 eq12, 12;

13 eq12, 13; 14 eq12, 14; 15 eq12, 15;

16 eq12, 16;

eq2 Orthogonalize1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11,

12, 13, 14, 15, 16 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1,

0, 0, 0, 0, 0, 0, 0,12

, 0, 0, 0,12

, 0,12

,12

, 0,

0, 0, 0,1

6, 0,

1

6,

1

6, 0, 0,

1

6,

1

6, 0,

1

6, 0, 0, 0,

0,12

,12

, 0,12

, 0, 0, 0,12

, 0, 0, 0, 0, 0, 0, 0,

1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,

0, 0, 0, 0, 0, 0, 0, 1

2, 0, 0, 0, 0, 0, 0,

1

2, 0,

0, 0, 0, 0, 0, 0, 0, 1

6, 0, 0, 0, 0, 0,

23

, 1

6, 0,

0, 0, 0, 1

2, 0, 0, 0, 0, 0, 0, 0, 0,

1

2, 0, 0, 0,

0, 0, 0, 0, 0, 0, 0, 1

2 3, 0, 0, 0,

32

, 0, 1

2 3,

1

2 3, 0,

0, 0, 0, 0, 0, 1

2, 0, 0, 0, 0,

1

2, 0, 0, 0, 0, 0,

0, 0, 0, 0, 0, 0, 1

2, 0, 0,

1

2, 0, 0, 0, 0, 0, 0,

0, 1

2, 0, 0, 0, 0, 0, 0,

1

2, 0, 0, 0, 0, 0, 0, 0,

0, 1

6, 0, 0,

23

, 0, 0, 0, 1

6, 0, 0, 0, 0, 0, 0, 0,

0, 1

2 3,

32

, 0, 1

2 3, 0, 0, 0,

1

2 3, 0, 0, 0, 0, 0, 0, 0,

0, 0, 0,12

, 0, 0, 12

, 0, 0, 12

, 0, 0,12

, 0, 0, 0,

0, 0, 0, 1

2 3, 0,

1

3,

1

2 3, 0, 0,

1

2 3,

1

3, 0,

1

2 3, 0, 0, 0

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21

1 eq24; 2 eq23; 3 eq22; 4 eq21; 5 eq25;

6 eq26; 7 eq27; 8 eq28; 9 eq29; 10 eq210;

11 eq211; 12 eq212; 13 eq213; 14 eq214;

15 eq215;

16 eq216;

Sz 1

2KroneckerProductz, I2, I2, I2 KroneckerProductI2, z, I2, I2

KroneckerProductI2, I2, z, I2 KroneckerProductI2, I2, I2, z;

Sz MatrixForm

2 0 0 0 0 0 0 0 0 0 0 0 0 0 0 00 1 0 0 0 0 0 0 0 0 0 0 0 0 0 00 0 1 0 0 0 0 0 0 0 0 0 0 0 0 00 0 0 0 0 0 0 0 0 0 0 0 0 0 0 00 0 0 0 1 0 0 0 0 0 0 0 0 0 0 00 0 0 0 0 0 0 0 0 0 0 0 0 0 0 00 0 0 0 0 0 0 0 0 0 0 0 0 0 0 00 0 0 0 0 0 0 1 0 0 0 0 0 0 0 00 0 0 0 0 0 0 0 1 0 0 0 0 0 0 00 0 0 0 0 0 0 0 0 0 0 0 0 0 0 00 0 0 0 0 0 0 0 0 0 0 0 0 0 0 00 0 0 0 0 0 0 0 0 0 0 1 0 0 0 00 0 0 0 0 0 0 0 0 0 0 0 0 0 0 00 0 0 0 0 0 0 0 0 0 0 0 0 1 0 00 0 0 0 0 0 0 0 0 0 0 0 0 0 1 00 0 0 0 0 0 0 0 0 0 0 0 0 0 0 2

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ST1.1 6 1

0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0

Sz.1 1

0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0

ST1.2 6 2

0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0

Sz.2

0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0

ST1.3 6 3

0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0

Sz.3 3

0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0

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ST1.4 6 4

0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0

Sz.4 2 4

0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0

ST1.5 6 5

0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0

Sz.5 2 5

0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0

ST1.6 2 6

0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0

Sz.6 6

0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0

ST1.7 2 7 Simplify

0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0

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Sz.7 7

0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0

ST1.8 2 8 Simplify

0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0

Sz.8

0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0

ST1.9 2 9 Simplify

0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0

Sz.9 9

0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0

ST1.10 2 10 Simplify

0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0

Sz.10

0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0

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ST1.11 2 11 Simplify

0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0

Sz.11

0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0

ST1.12 2 12 Simplify

0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0

Sz.12 12

0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0

ST1.13 2 13 Simplify

0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0

Sz.13 13

0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0

ST1.14 2 14 Simplify

0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0

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Sz.14 14

0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0

ST1.15 Simplify

0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0

Sz.15

0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0

ST1.16 Simplify

0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0

Sz.16

0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0

4.5, 5.6, 6.7, 7.80, 0, 0, 01

0,12

,12

, 0,12

, 0, 0, 0,12

, 0, 0, 0, 0, 0, 0, 0

2

0, 0, 0,1

6, 0,

1

6,

1

6, 0, 0,

1

6,

1

6, 0,

1

6, 0, 0, 0

3

0, 0, 0, 0, 0, 0, 0,12

, 0, 0, 0,12

, 0,12

,12

, 0

4

0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1

5

1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0

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6

0, 0, 0, 0, 0, 0, 0, 1

2, 0, 0, 0, 0, 0, 0,

1

2, 0

7

0, 0, 0, 0, 0, 0, 0, 1

6, 0, 0, 0, 0, 0,

23

, 1

6, 0

8

0, 0, 0, 1

2, 0, 0, 0, 0, 0, 0, 0, 0,

1

2, 0, 0, 0

9

0, 0, 0, 0, 0, 0, 0, 1

2 3, 0, 0, 0,

32

, 0, 1

2 3,

1

2 3, 0

10

0, 0, 0, 0, 0, 1

2, 0, 0, 0, 0,

1

2, 0, 0, 0, 0, 0

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____________________________________________________________________________ REFERENCES L.I. Schiff, Quantum Mechanics third edition (McGraw-Hill Book Company, New York, 1968). S. Tomonaga, Angylar momentum and spin (Misuzu, Toyo, 1989). D.M. Brink and G.R. Satcher, Angular Momentum, second edition (Clarendon Press, Oxford,

1966). Nouredine Zettili, Quantum Mechanics, Concepts and Applications, 2nd edition (John Wiley &

Sons, New York, 2009).

_____________________________________________________________________________ APPENDIX Mathematica 1. Clebsch-Gordan coefficient

11

0, 0, 0, 0, 0, 0, 1

2, 0, 0,

1

2, 0, 0, 0, 0, 0, 0

12

0, 1

2, 0, 0, 0, 0, 0, 0,

1

2, 0, 0, 0, 0, 0, 0, 0

13

0, 1

6, 0, 0,

23

, 0, 0, 0, 1

6, 0, 0, 0, 0, 0, 0, 0

14

0, 1

2 3,

32

, 0, 1

2 3, 0, 0, 0,

1

2 3, 0, 0, 0, 0, 0, 0, 0

15

0, 0, 0,12

, 0, 0, 12

, 0, 0, 12

, 0, 0,12

, 0, 0, 0

16

0, 0, 0, 1

2 3, 0,

1

3,

1

2 3, 0, 0,

1

2 3,

1

3, 0,

1

2 3, 0, 0, 0

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2. KroneckerProduct

3. Eigensystem

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