Decomposing the “sign flip” matrix in terms of Pauli matrices

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Can the matrix:



$A=left[beginmatrix0 & -1 \ -1 & 0endmatrixright]$



be somehow expressed as a product of the $3$ standard Pauli matrices?



I'm being able to diagonalize $A$, but not sure if it can be expressed in terms of Pauli-X, Y, Z.







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    up vote
    3
    down vote

    favorite












    Can the matrix:



    $A=left[beginmatrix0 & -1 \ -1 & 0endmatrixright]$



    be somehow expressed as a product of the $3$ standard Pauli matrices?



    I'm being able to diagonalize $A$, but not sure if it can be expressed in terms of Pauli-X, Y, Z.







    share|cite|improve this question





















      up vote
      3
      down vote

      favorite









      up vote
      3
      down vote

      favorite











      Can the matrix:



      $A=left[beginmatrix0 & -1 \ -1 & 0endmatrixright]$



      be somehow expressed as a product of the $3$ standard Pauli matrices?



      I'm being able to diagonalize $A$, but not sure if it can be expressed in terms of Pauli-X, Y, Z.







      share|cite|improve this question











      Can the matrix:



      $A=left[beginmatrix0 & -1 \ -1 & 0endmatrixright]$



      be somehow expressed as a product of the $3$ standard Pauli matrices?



      I'm being able to diagonalize $A$, but not sure if it can be expressed in terms of Pauli-X, Y, Z.









      share|cite|improve this question










      share|cite|improve this question




      share|cite|improve this question









      asked Jul 27 at 23:20









      Blue

      15617




      15617




















          2 Answers
          2






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          oldest

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          up vote
          2
          down vote



          accepted










          I start by knowing that the flip operator is $F=-sigma_1$.



          Then to express as a product of all the sigma matrices we just find a combination which reduces to the negative identity.



          The relation



          $$sigma_1^2 = sigma_2^2=sigma_3^2=-isigma_1sigma_2sigma_3 = 1$$



          lets us construct $(sigma_1sigma_2sigma_3)^2 = -1$ to get



          $$F=-sigma_1(sigma_1sigma_2sigma_3)^2$$
          $$requirecancel F=-cancelsigma_1sigma_1sigma_2sigma_3sigma_1sigma_2sigma_3$$



          We can also recover the solution provided by @euler-is-alive because $sigma_1sigma_2sigma_3=i$ is just a number and so we can freely rearrange as $sigma_1sigma_2sigma_3sigma_2sigma_3$






          share|cite|improve this answer





















          • More of a comment but I also thought it's interesting that $F = -sigma_1 = isigma_2sigma_3$
            – Alexander McFarlane
            Jul 28 at 1:27

















          up vote
          3
          down vote













          $beginbmatrix 0 & -1\ -1 & 0endbmatrix = beginbmatrix 0 & 1\ 1 & 0endbmatrix beginbmatrix 0 & -i\ i & 0endbmatrix beginbmatrix 1 & 0\ 0 & -1endbmatrix beginbmatrix 0 & -i\ i & 0endbmatrix beginbmatrix 1 & 0\ 0 & -1endbmatrix $






          share|cite|improve this answer





















          • Nice! How exactly did you come up with the decomposition?
            – Blue
            Jul 27 at 23:42






          • 1




            You're probably not going to like my answer. I had never heard of the Pauli Matrices before, so I looked them up on Wikipedia, and played around with them for about 5 minutes finding out some properties. There may very well in fact be other decompositions that are more useful for what you are looking for.
            – Euler....IS_ALIVE
            Jul 27 at 23:53










          • (Note that since the matrices are involutory, the last 4 terms are simply the multiplicative commutator).
            – Euler....IS_ALIVE
            Jul 28 at 0:04










          Your Answer




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          2 Answers
          2






          active

          oldest

          votes








          2 Answers
          2






          active

          oldest

          votes









          active

          oldest

          votes






          active

          oldest

          votes








          up vote
          2
          down vote



          accepted










          I start by knowing that the flip operator is $F=-sigma_1$.



          Then to express as a product of all the sigma matrices we just find a combination which reduces to the negative identity.



          The relation



          $$sigma_1^2 = sigma_2^2=sigma_3^2=-isigma_1sigma_2sigma_3 = 1$$



          lets us construct $(sigma_1sigma_2sigma_3)^2 = -1$ to get



          $$F=-sigma_1(sigma_1sigma_2sigma_3)^2$$
          $$requirecancel F=-cancelsigma_1sigma_1sigma_2sigma_3sigma_1sigma_2sigma_3$$



          We can also recover the solution provided by @euler-is-alive because $sigma_1sigma_2sigma_3=i$ is just a number and so we can freely rearrange as $sigma_1sigma_2sigma_3sigma_2sigma_3$






          share|cite|improve this answer





















          • More of a comment but I also thought it's interesting that $F = -sigma_1 = isigma_2sigma_3$
            – Alexander McFarlane
            Jul 28 at 1:27














          up vote
          2
          down vote



          accepted










          I start by knowing that the flip operator is $F=-sigma_1$.



          Then to express as a product of all the sigma matrices we just find a combination which reduces to the negative identity.



          The relation



          $$sigma_1^2 = sigma_2^2=sigma_3^2=-isigma_1sigma_2sigma_3 = 1$$



          lets us construct $(sigma_1sigma_2sigma_3)^2 = -1$ to get



          $$F=-sigma_1(sigma_1sigma_2sigma_3)^2$$
          $$requirecancel F=-cancelsigma_1sigma_1sigma_2sigma_3sigma_1sigma_2sigma_3$$



          We can also recover the solution provided by @euler-is-alive because $sigma_1sigma_2sigma_3=i$ is just a number and so we can freely rearrange as $sigma_1sigma_2sigma_3sigma_2sigma_3$






          share|cite|improve this answer





















          • More of a comment but I also thought it's interesting that $F = -sigma_1 = isigma_2sigma_3$
            – Alexander McFarlane
            Jul 28 at 1:27












          up vote
          2
          down vote



          accepted







          up vote
          2
          down vote



          accepted






          I start by knowing that the flip operator is $F=-sigma_1$.



          Then to express as a product of all the sigma matrices we just find a combination which reduces to the negative identity.



          The relation



          $$sigma_1^2 = sigma_2^2=sigma_3^2=-isigma_1sigma_2sigma_3 = 1$$



          lets us construct $(sigma_1sigma_2sigma_3)^2 = -1$ to get



          $$F=-sigma_1(sigma_1sigma_2sigma_3)^2$$
          $$requirecancel F=-cancelsigma_1sigma_1sigma_2sigma_3sigma_1sigma_2sigma_3$$



          We can also recover the solution provided by @euler-is-alive because $sigma_1sigma_2sigma_3=i$ is just a number and so we can freely rearrange as $sigma_1sigma_2sigma_3sigma_2sigma_3$






          share|cite|improve this answer













          I start by knowing that the flip operator is $F=-sigma_1$.



          Then to express as a product of all the sigma matrices we just find a combination which reduces to the negative identity.



          The relation



          $$sigma_1^2 = sigma_2^2=sigma_3^2=-isigma_1sigma_2sigma_3 = 1$$



          lets us construct $(sigma_1sigma_2sigma_3)^2 = -1$ to get



          $$F=-sigma_1(sigma_1sigma_2sigma_3)^2$$
          $$requirecancel F=-cancelsigma_1sigma_1sigma_2sigma_3sigma_1sigma_2sigma_3$$



          We can also recover the solution provided by @euler-is-alive because $sigma_1sigma_2sigma_3=i$ is just a number and so we can freely rearrange as $sigma_1sigma_2sigma_3sigma_2sigma_3$







          share|cite|improve this answer













          share|cite|improve this answer



          share|cite|improve this answer











          answered Jul 28 at 1:24









          Alexander McFarlane

          1,018518




          1,018518











          • More of a comment but I also thought it's interesting that $F = -sigma_1 = isigma_2sigma_3$
            – Alexander McFarlane
            Jul 28 at 1:27
















          • More of a comment but I also thought it's interesting that $F = -sigma_1 = isigma_2sigma_3$
            – Alexander McFarlane
            Jul 28 at 1:27















          More of a comment but I also thought it's interesting that $F = -sigma_1 = isigma_2sigma_3$
          – Alexander McFarlane
          Jul 28 at 1:27




          More of a comment but I also thought it's interesting that $F = -sigma_1 = isigma_2sigma_3$
          – Alexander McFarlane
          Jul 28 at 1:27










          up vote
          3
          down vote













          $beginbmatrix 0 & -1\ -1 & 0endbmatrix = beginbmatrix 0 & 1\ 1 & 0endbmatrix beginbmatrix 0 & -i\ i & 0endbmatrix beginbmatrix 1 & 0\ 0 & -1endbmatrix beginbmatrix 0 & -i\ i & 0endbmatrix beginbmatrix 1 & 0\ 0 & -1endbmatrix $






          share|cite|improve this answer





















          • Nice! How exactly did you come up with the decomposition?
            – Blue
            Jul 27 at 23:42






          • 1




            You're probably not going to like my answer. I had never heard of the Pauli Matrices before, so I looked them up on Wikipedia, and played around with them for about 5 minutes finding out some properties. There may very well in fact be other decompositions that are more useful for what you are looking for.
            – Euler....IS_ALIVE
            Jul 27 at 23:53










          • (Note that since the matrices are involutory, the last 4 terms are simply the multiplicative commutator).
            – Euler....IS_ALIVE
            Jul 28 at 0:04














          up vote
          3
          down vote













          $beginbmatrix 0 & -1\ -1 & 0endbmatrix = beginbmatrix 0 & 1\ 1 & 0endbmatrix beginbmatrix 0 & -i\ i & 0endbmatrix beginbmatrix 1 & 0\ 0 & -1endbmatrix beginbmatrix 0 & -i\ i & 0endbmatrix beginbmatrix 1 & 0\ 0 & -1endbmatrix $






          share|cite|improve this answer





















          • Nice! How exactly did you come up with the decomposition?
            – Blue
            Jul 27 at 23:42






          • 1




            You're probably not going to like my answer. I had never heard of the Pauli Matrices before, so I looked them up on Wikipedia, and played around with them for about 5 minutes finding out some properties. There may very well in fact be other decompositions that are more useful for what you are looking for.
            – Euler....IS_ALIVE
            Jul 27 at 23:53










          • (Note that since the matrices are involutory, the last 4 terms are simply the multiplicative commutator).
            – Euler....IS_ALIVE
            Jul 28 at 0:04












          up vote
          3
          down vote










          up vote
          3
          down vote









          $beginbmatrix 0 & -1\ -1 & 0endbmatrix = beginbmatrix 0 & 1\ 1 & 0endbmatrix beginbmatrix 0 & -i\ i & 0endbmatrix beginbmatrix 1 & 0\ 0 & -1endbmatrix beginbmatrix 0 & -i\ i & 0endbmatrix beginbmatrix 1 & 0\ 0 & -1endbmatrix $






          share|cite|improve this answer













          $beginbmatrix 0 & -1\ -1 & 0endbmatrix = beginbmatrix 0 & 1\ 1 & 0endbmatrix beginbmatrix 0 & -i\ i & 0endbmatrix beginbmatrix 1 & 0\ 0 & -1endbmatrix beginbmatrix 0 & -i\ i & 0endbmatrix beginbmatrix 1 & 0\ 0 & -1endbmatrix $







          share|cite|improve this answer













          share|cite|improve this answer



          share|cite|improve this answer











          answered Jul 27 at 23:40









          Euler....IS_ALIVE

          2,51511036




          2,51511036











          • Nice! How exactly did you come up with the decomposition?
            – Blue
            Jul 27 at 23:42






          • 1




            You're probably not going to like my answer. I had never heard of the Pauli Matrices before, so I looked them up on Wikipedia, and played around with them for about 5 minutes finding out some properties. There may very well in fact be other decompositions that are more useful for what you are looking for.
            – Euler....IS_ALIVE
            Jul 27 at 23:53










          • (Note that since the matrices are involutory, the last 4 terms are simply the multiplicative commutator).
            – Euler....IS_ALIVE
            Jul 28 at 0:04
















          • Nice! How exactly did you come up with the decomposition?
            – Blue
            Jul 27 at 23:42






          • 1




            You're probably not going to like my answer. I had never heard of the Pauli Matrices before, so I looked them up on Wikipedia, and played around with them for about 5 minutes finding out some properties. There may very well in fact be other decompositions that are more useful for what you are looking for.
            – Euler....IS_ALIVE
            Jul 27 at 23:53










          • (Note that since the matrices are involutory, the last 4 terms are simply the multiplicative commutator).
            – Euler....IS_ALIVE
            Jul 28 at 0:04















          Nice! How exactly did you come up with the decomposition?
          – Blue
          Jul 27 at 23:42




          Nice! How exactly did you come up with the decomposition?
          – Blue
          Jul 27 at 23:42




          1




          1




          You're probably not going to like my answer. I had never heard of the Pauli Matrices before, so I looked them up on Wikipedia, and played around with them for about 5 minutes finding out some properties. There may very well in fact be other decompositions that are more useful for what you are looking for.
          – Euler....IS_ALIVE
          Jul 27 at 23:53




          You're probably not going to like my answer. I had never heard of the Pauli Matrices before, so I looked them up on Wikipedia, and played around with them for about 5 minutes finding out some properties. There may very well in fact be other decompositions that are more useful for what you are looking for.
          – Euler....IS_ALIVE
          Jul 27 at 23:53












          (Note that since the matrices are involutory, the last 4 terms are simply the multiplicative commutator).
          – Euler....IS_ALIVE
          Jul 28 at 0:04




          (Note that since the matrices are involutory, the last 4 terms are simply the multiplicative commutator).
          – Euler....IS_ALIVE
          Jul 28 at 0:04












           

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