Is there a difference of sign conventions of Dirac Index between mathematics and physics?












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In section 12.6.2 of Nakahara, on a four dimensional manifold, the index of a twisted Dirac operator is given by



$$mathrm{Ind}(D!!!!/_{A})=frac{-1}{8pi^{2}}int_{M}mathrm{Tr}(Fwedge F)+frac{dim_{mathbb{C}}E}{192pi^{2}}int_{M}mathrm{Tr}(Rwedge R),$$



where $E$ is a vector bundle over $M$, $D!!!!/_{A}$ is a Dirac operator twisted by the gauge field $A$, $F$ is the assocciated field strength, and $R$ is the Riemann tensor of $M$.



However, in Strongly Correlated Electrons
Gapped Boundary Phases of Topological Insulators via Weak Coupling by
Nathan Seiberg and Edward Witten, their version of index theorem is



$$mathrm{Ind}(D!!!!/_{A})=intleft(frac{Fwedge F}{8pi^{2}}+widehat{A}(R)right),$$



where the sign of the second chern character differs from that in Nakahara.



Is this related with the different conventions of Lie algebra (Hermitian in physics vs. Anti-Hermitian in mathematics) between the two communities?



I also posted this question here.










share|cite|improve this question









$endgroup$

















    0












    $begingroup$


    In section 12.6.2 of Nakahara, on a four dimensional manifold, the index of a twisted Dirac operator is given by



    $$mathrm{Ind}(D!!!!/_{A})=frac{-1}{8pi^{2}}int_{M}mathrm{Tr}(Fwedge F)+frac{dim_{mathbb{C}}E}{192pi^{2}}int_{M}mathrm{Tr}(Rwedge R),$$



    where $E$ is a vector bundle over $M$, $D!!!!/_{A}$ is a Dirac operator twisted by the gauge field $A$, $F$ is the assocciated field strength, and $R$ is the Riemann tensor of $M$.



    However, in Strongly Correlated Electrons
    Gapped Boundary Phases of Topological Insulators via Weak Coupling by
    Nathan Seiberg and Edward Witten, their version of index theorem is



    $$mathrm{Ind}(D!!!!/_{A})=intleft(frac{Fwedge F}{8pi^{2}}+widehat{A}(R)right),$$



    where the sign of the second chern character differs from that in Nakahara.



    Is this related with the different conventions of Lie algebra (Hermitian in physics vs. Anti-Hermitian in mathematics) between the two communities?



    I also posted this question here.










    share|cite|improve this question









    $endgroup$















      0












      0








      0





      $begingroup$


      In section 12.6.2 of Nakahara, on a four dimensional manifold, the index of a twisted Dirac operator is given by



      $$mathrm{Ind}(D!!!!/_{A})=frac{-1}{8pi^{2}}int_{M}mathrm{Tr}(Fwedge F)+frac{dim_{mathbb{C}}E}{192pi^{2}}int_{M}mathrm{Tr}(Rwedge R),$$



      where $E$ is a vector bundle over $M$, $D!!!!/_{A}$ is a Dirac operator twisted by the gauge field $A$, $F$ is the assocciated field strength, and $R$ is the Riemann tensor of $M$.



      However, in Strongly Correlated Electrons
      Gapped Boundary Phases of Topological Insulators via Weak Coupling by
      Nathan Seiberg and Edward Witten, their version of index theorem is



      $$mathrm{Ind}(D!!!!/_{A})=intleft(frac{Fwedge F}{8pi^{2}}+widehat{A}(R)right),$$



      where the sign of the second chern character differs from that in Nakahara.



      Is this related with the different conventions of Lie algebra (Hermitian in physics vs. Anti-Hermitian in mathematics) between the two communities?



      I also posted this question here.










      share|cite|improve this question









      $endgroup$




      In section 12.6.2 of Nakahara, on a four dimensional manifold, the index of a twisted Dirac operator is given by



      $$mathrm{Ind}(D!!!!/_{A})=frac{-1}{8pi^{2}}int_{M}mathrm{Tr}(Fwedge F)+frac{dim_{mathbb{C}}E}{192pi^{2}}int_{M}mathrm{Tr}(Rwedge R),$$



      where $E$ is a vector bundle over $M$, $D!!!!/_{A}$ is a Dirac operator twisted by the gauge field $A$, $F$ is the assocciated field strength, and $R$ is the Riemann tensor of $M$.



      However, in Strongly Correlated Electrons
      Gapped Boundary Phases of Topological Insulators via Weak Coupling by
      Nathan Seiberg and Edward Witten, their version of index theorem is



      $$mathrm{Ind}(D!!!!/_{A})=intleft(frac{Fwedge F}{8pi^{2}}+widehat{A}(R)right),$$



      where the sign of the second chern character differs from that in Nakahara.



      Is this related with the different conventions of Lie algebra (Hermitian in physics vs. Anti-Hermitian in mathematics) between the two communities?



      I also posted this question here.







      characteristic-classes convention






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      asked Dec 19 '18 at 14:57









      The Last Knight of Silk RoadThe Last Knight of Silk Road

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