2D representation of 3D algebra












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I'm working with a Lie algebra that has 3 generator, $t_i$, that satisfy the following rules:



$$[t_2, t_3] = it_2, quad [t_3, t_1] = it_1, quad [t_1, t_2] = it_3 tag1$$



A 3D representation is easy if we choose the adjoint representation, but I want a 2D representation. I'm trying computing the commutators (with general $2times 2$ matrices) but I got non-sense results like parameter equal its negative or a generator with a zero in all entries. Does anyone know a more efficient method to compute this or know a group with this algebra?










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    I'm working with a Lie algebra that has 3 generator, $t_i$, that satisfy the following rules:



    $$[t_2, t_3] = it_2, quad [t_3, t_1] = it_1, quad [t_1, t_2] = it_3 tag1$$



    A 3D representation is easy if we choose the adjoint representation, but I want a 2D representation. I'm trying computing the commutators (with general $2times 2$ matrices) but I got non-sense results like parameter equal its negative or a generator with a zero in all entries. Does anyone know a more efficient method to compute this or know a group with this algebra?










    share|cite|improve this question

























      0












      0








      0







      I'm working with a Lie algebra that has 3 generator, $t_i$, that satisfy the following rules:



      $$[t_2, t_3] = it_2, quad [t_3, t_1] = it_1, quad [t_1, t_2] = it_3 tag1$$



      A 3D representation is easy if we choose the adjoint representation, but I want a 2D representation. I'm trying computing the commutators (with general $2times 2$ matrices) but I got non-sense results like parameter equal its negative or a generator with a zero in all entries. Does anyone know a more efficient method to compute this or know a group with this algebra?










      share|cite|improve this question













      I'm working with a Lie algebra that has 3 generator, $t_i$, that satisfy the following rules:



      $$[t_2, t_3] = it_2, quad [t_3, t_1] = it_1, quad [t_1, t_2] = it_3 tag1$$



      A 3D representation is easy if we choose the adjoint representation, but I want a 2D representation. I'm trying computing the commutators (with general $2times 2$ matrices) but I got non-sense results like parameter equal its negative or a generator with a zero in all entries. Does anyone know a more efficient method to compute this or know a group with this algebra?







      abstract-algebra group-theory lie-groups lie-algebras






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      asked Nov 18 at 16:09









      Vicky

      1437




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          It deals with SU(2). Take for the $t_k$ a representation by Pauli matrices $sigma_k$ as well explained in the following document :{http://hepwww.rl.ac.uk/Haywood/Group_Theory_Lectures/Lecture_3.pdf} where $epsilon_{ijk}$ is the classical alternate tensor ($epsilon_{ijk}=1$ if $(i,j,k)$ is an even permutation of $(1,2,3)$, $epsilon_{ijk}=-1$ otherwise). The presence of this tensor explains why the three identities you have given do not look connected by a circular permutation of indices.






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          • Yes, you are absolutely right. How didn't I see it? Thank you very much!
            – Vicky
            Nov 18 at 16:38











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          It deals with SU(2). Take for the $t_k$ a representation by Pauli matrices $sigma_k$ as well explained in the following document :{http://hepwww.rl.ac.uk/Haywood/Group_Theory_Lectures/Lecture_3.pdf} where $epsilon_{ijk}$ is the classical alternate tensor ($epsilon_{ijk}=1$ if $(i,j,k)$ is an even permutation of $(1,2,3)$, $epsilon_{ijk}=-1$ otherwise). The presence of this tensor explains why the three identities you have given do not look connected by a circular permutation of indices.






          share|cite|improve this answer





















          • Yes, you are absolutely right. How didn't I see it? Thank you very much!
            – Vicky
            Nov 18 at 16:38
















          1














          It deals with SU(2). Take for the $t_k$ a representation by Pauli matrices $sigma_k$ as well explained in the following document :{http://hepwww.rl.ac.uk/Haywood/Group_Theory_Lectures/Lecture_3.pdf} where $epsilon_{ijk}$ is the classical alternate tensor ($epsilon_{ijk}=1$ if $(i,j,k)$ is an even permutation of $(1,2,3)$, $epsilon_{ijk}=-1$ otherwise). The presence of this tensor explains why the three identities you have given do not look connected by a circular permutation of indices.






          share|cite|improve this answer





















          • Yes, you are absolutely right. How didn't I see it? Thank you very much!
            – Vicky
            Nov 18 at 16:38














          1












          1








          1






          It deals with SU(2). Take for the $t_k$ a representation by Pauli matrices $sigma_k$ as well explained in the following document :{http://hepwww.rl.ac.uk/Haywood/Group_Theory_Lectures/Lecture_3.pdf} where $epsilon_{ijk}$ is the classical alternate tensor ($epsilon_{ijk}=1$ if $(i,j,k)$ is an even permutation of $(1,2,3)$, $epsilon_{ijk}=-1$ otherwise). The presence of this tensor explains why the three identities you have given do not look connected by a circular permutation of indices.






          share|cite|improve this answer












          It deals with SU(2). Take for the $t_k$ a representation by Pauli matrices $sigma_k$ as well explained in the following document :{http://hepwww.rl.ac.uk/Haywood/Group_Theory_Lectures/Lecture_3.pdf} where $epsilon_{ijk}$ is the classical alternate tensor ($epsilon_{ijk}=1$ if $(i,j,k)$ is an even permutation of $(1,2,3)$, $epsilon_{ijk}=-1$ otherwise). The presence of this tensor explains why the three identities you have given do not look connected by a circular permutation of indices.







          share|cite|improve this answer












          share|cite|improve this answer



          share|cite|improve this answer










          answered Nov 18 at 16:30









          Jean Marie

          28.8k41949




          28.8k41949












          • Yes, you are absolutely right. How didn't I see it? Thank you very much!
            – Vicky
            Nov 18 at 16:38


















          • Yes, you are absolutely right. How didn't I see it? Thank you very much!
            – Vicky
            Nov 18 at 16:38
















          Yes, you are absolutely right. How didn't I see it? Thank you very much!
          – Vicky
          Nov 18 at 16:38




          Yes, you are absolutely right. How didn't I see it? Thank you very much!
          – Vicky
          Nov 18 at 16:38


















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