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# Generalizations For Cartans Equations And Bianchi Identities For Arbitrary Dimensions And Its Actions

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### Generalizations For Cartans Equations And Bianchi Identities For Arbitrary Dimensions And Its Actions

1. 1. Generalizations for Cartan’s equations and Bianchi identities for arbitrary dimensions and its actions Vladimir Cuesta † Instituto de Ciencias Nucleares, Universidad Nacional Aut´onoma de M´exico, 70-543, Ciudad de M´exico, M´exico Abstract. Cartan’s ﬁrst and second structure equations are sets of equations for 2-forms, in a similar way ﬁrst and second Bianchi identities are sets of equations for 3-forms involving exterior derivatives and wedge products between the tetrad, the connection, the torsion and the curvature. However, I can add parameters and wedge products between my set of variables and I ﬁnd equations for 2-forms and 3-forms involving exterior derivatives and wedge products and these equations contain Cartan’s equations and Bianchi’s identities like particular cases, I made that in my study. Now, If I think the tetrad, the connection, the torsion and the curvature as independent variables I can construct actions for my generalizations for arbitrary dimensions introducing auxiliary ﬁelds. I can generalize in some sense the work in [1]. 1. Introduction Differential geometry is of great importance for the mathematics of our days (see [2] and [3] for instance), inside this area we can ﬁnd the study of differential forms and like a lot of studies, there are intersections between different areas of knowledge, in the case of differential forms, I can make studies for actions, studies for geometry, algebra, analysis, functional analysis and so on. In the present paper I will ﬁnd equations that are generalizations for the Cartan’s structure equations and Bianchi identities, I will divide my studies for the two-dimensional case, the three- dimensional case and the n-dimensional case, in this paper I introduce a set of parameters and wedge products for my basic variables for making the generalization. My basic variables are the one-forms eI or tetrad and the ﬁeld φI , the one-forms ωI J or connection and the ﬁeld φI J , the two-forms TI or torsion and the ﬁeld ψI and the two-forms RI J or curvature and the ﬁeld ψI J (see [1] for instance). I will begin with the discussion as follows: † vladimir.cuesta@nucleares.unam.mx
2. 2. Generalizations for Cartan’s equations and Bianchi identities for arbitrary dimensions and its actions2 The Cartan’s ﬁrst structure equations, deI + ωI K ∧ eK = TI , (1) are set of equations for two-forms where I is free with the d exterior derivative and wedge product as operations. The Cartan’s second structure equations, dωIJ + ωI K ∧ ωKJ = RIJ , (2) are set of equations for two-forms where I and J are free with the d exterior derivative and wedge product as operations. The ﬁrst Bianchi identities, dTI + ωI K ∧ TK = RI K ∧ eK , (3) are set of equations for three-forms where I is free with the d exterior derivative and wedge product as operations. The second Bianchi identities, dRIJ + ωI K ∧ RKJ − ωJ K ∧ RKI = 0, (4) are set of equations for three-forms where I and J are free with the d exterior derivative and wedge product as operations. In all the previous equations, the indices I, J, . . ., are raised and lowered with the Minkowski (σ = −1) or Euclidean (σ = +1) metric (ηIJ ) = diag(σ, +1, +1, . . . , +1). In the present paper I will construct a set of equations with the same structure like all Cartan’s structure equations and Bianchi’s identities (see [4] and [5] for a comprehensive exposition). I mean, set of equations for two-forms where I is free with the d exterior derivative and wedge product as operations, set of equations for two-forms where I and J are free with the d exterior derivative and wedge product as operations, set of equations for three-forms where I is free with the d exterior derivative and wedge product as operations and set of equations for three-forms where I and J are free with the d exterior derivative and wedge product as operations, in my formalism the basic variables eI , φI , ωI J , φI J , TI , ψI , RI J and ψI J , I present actions for my equations of motion. 2. Bi-dimensional case In two dimensions, I can construct the following action: I2 = [φIdeI + φIJ dωIJ − a1φIωI K ∧ eK − a2φITI − b1φIJ RIJ − b2φIJ ωI K ∧ ωKJ − b3φIJ eI ∧ eJ ] = [−dφI ∧ eI − dφIJ ∧ ωIJ − a1φIωI K ∧ eK − a2φITI − b1φIJ RIJ − b2φIJ ωI K ∧ ωKJ − b3φIJ eI ∧ eJ ], (5)
3. 3. Generalizations for Cartan’s equations and Bianchi identities for arbitrary dimensions and its actions3 where eI is the tetrad, ωIJ is the connection, TI is the torsion, RIJ is the curvature, φI and φIJ are zero-forms. I can vary the action and I obtain my equations of motion: δφI : deI − a1ωI K ∧ eK − a2TI = 0, δφIJ : dωIJ − b1RIJ − b2ωI K ∧ ωKJ − b3eI ∧ eJ = 0, δeI : dφI + a1φKωK I + 2b3φKIeK = 0, δωIJ : − dφIJ + a1φ[IeJ] + 2b2φ[I|Kω|J] K = 0, (6) 3. Three-dimensional case In this case I choose the 1-forms φI, φIJ , the 0-forms ψI, ψIJ and my action principle is (see [6] for an early discussion of the subject): I3 = [φI ∧ deI + φIJ ∧ dωIJ + ψIJ dRIJ + ψIdTI − a1φI ∧ ωI K ∧ eK − a2φI ∧ TI − b1φIJ ∧ RIJ − b2φIJ ∧ ωI K ∧ ωKJ − b3φIJ ∧ eI ∧ eJ + a1b1 a2 ψIRI K ∧ eK − a1ψIωI K ∧ TK − a1(a1 − b2) a2 ψIωI K ∧ ωK L ∧ eL − 2b2ψIJ ωI K ∧ RKJ − 2b3a2 b1 ψIJ eI ∧ TJ − 2b3(a1 − b2) b1 ψIJ eI ∧ eK ∧ ωK J ] = [dφI ∧ eI + dφIJ ∧ ωIJ − dψIJ ∧ RIJ − dψI ∧ TI − a1φI ∧ ωI K ∧ eK − a2φI ∧ TI − b1φIJ ∧ RIJ − b2φIJ ∧ ωI K ∧ ωKJ − b3φIJ ∧ eI ∧ eJ + a1b1 a2 ψIRI K ∧ eK − a1ψIωI K ∧ TK − a1(a1 − b2) a2 ψIωI K ∧ ωK L ∧ eL − 2b2ψIJ ωI K ∧ RKJ − 2b3a2 b1 ψIJ eI ∧ TJ − 2b3(a1 − b2) b1 ψIJ eI ∧ eK ∧ ωK J ], (7) I can consider my independent variables as φI, φIJ , ψI, ψIJ , eI , ωIJ , RIJ and TI , I must vary the previous action and I obtain the following set of equations: δφI : deI − a1ωI K ∧ eK − a2TI = 0, δφIJ : dωIJ − b1RIJ − b2ωI K ∧ ωKJ − b3eI ∧ eJ = 0, δψI : dTI + a1b1 a2 RI K ∧ eK − a1ωI K ∧ TK − a1(a1 − b2) a2 ωI K ∧ ωK L ∧ eL = 0, δψIJ : dRIJ − b2 ωI K ∧ RKJ − ωJ K ∧ RKI − b3a2 b1 eI ∧ TJ − eJ ∧ TI ) − b3(a1 − b2) b1 eI ∧ eK ∧ ωK J − eJ ∧ eK ∧ ωK I = 0, δeI : dφI − a1φK ∧ ωK I + 2b3φIK ∧ eK + a1b1 a2 ψKRK I
4. 4. Generalizations for Cartan’s equations and Bianchi identities for arbitrary dimensions and its actions4 − a1(a1 − b2) a2 ψN ωN K ∧ ωK I + 4b3a2 b1 ψIKeK − 2b3(a1 − b2) b1 ψKN ωI N ∧ eK + 2b3(a1 − b2) b1 ψIN ωK N ∧ eK = 0, δωIJ : dφIJ + a1φ[I ∧ eJ] + 2b2φ[I|K ∧ ω|J] K − a1ψ[I|T|J] + a1(a1 − b2) a2 ψKe[I| ∧ ωK |J] + a1(a1 − b2) a2 ψ[I|eK ∧ ω|J] K − 2b2ψ[I|KR|J] K + 2b3(a1 − b2) b1 ψK[I|eK ∧ e|J] = 0, δRIJ : − dψIJ − b1φIJ + a1b1 a2 ψ[I|e|J] + 2b2ψK[I|ωK |J] = 0, δTI : dψI + a2φI + a1ψKωK I = 0, (8) 4. n-dimensional case In this case I choose the (n-2)-forms φI, φIJ and the (n-3)-forms ψI, ψIJ and my action principle is: In = [φI ∧ deI + φIJ ∧ dωIJ + ψIJ ∧ dRIJ + ψI ∧ dTI − a1φI ∧ ωI K ∧ eK − a2φI ∧ TI − b1φIJ ∧ RIJ − b2φIJ ∧ ωI K ∧ ωKJ − b3φIJ ∧ eI ∧ eJ + a1b1 a2 ψI ∧ RI K ∧ eK − a1ψI ∧ ωI K ∧ TK − a1(a1 − b2) a2 ψI ∧ ωI K ∧ ωK L ∧ eL − 2b2ψIJ ∧ ωI K ∧ RKJ − 2b3a2 b1 ψIJ ∧ eI ∧ TJ − 2b3(a1 − b2) b1 ψIJ ∧ eI ∧ eK ∧ ωK J ] = [−(−1)n dφI ∧ eI − (−1)n dφIJ ∧ ωIJ + (−1)n dψIJ ∧ RIJ + (−1)n dψI ∧ TI − a1φI ∧ ωI K ∧ eK − a2φI ∧ TI − b1φIJ ∧ RIJ − b2φIJ ∧ ωI K ∧ ωKJ − b3φIJ ∧ eI ∧ eJ + a1b1 a2 ψI ∧ RI K ∧ eK − a1ψI ∧ ωI K ∧ TK − a1(a1 − b2) a2 ψI ∧ ωI K ∧ ωK L ∧ eL − 2b2ψIJ ∧ ωI K ∧ RKJ − 2b3a2 b1 ψIJ ∧ eI ∧ TJ − 2b3(a1 − b2) b1 ψIJ ∧ eI ∧ eK ∧ ωK J ], (9) I can consider my independent variables to φI, φIJ , ψI, ψIJ , eI , ωIJ , RIJ and TI , I must vary the previous action and I obtain the following set of equations: δφI : deI − a1ωI K ∧ eK − a2TI = 0, δφIJ : dωIJ − b1RIJ − b2ωI K ∧ ωKJ − b3eI ∧ eJ = 0, δψI : dTI + a1b1 a2 RI K ∧ eK − a1ωI K ∧ TK − a1(a1 − b2) a2 ωI K ∧ ωK L ∧ eL = 0,
5. 5. Generalizations for Cartan’s equations and Bianchi identities for arbitrary dimensions and its actions5 δψIJ : dRIJ − b2 ωI K ∧ RKJ − ωJ K ∧ RKI − b3a2 b1 eI ∧ TJ − eJ ∧ TI ) − b3(a1 − b2) b1 eI ∧ eK ∧ ωK J − eJ ∧ eK ∧ ωK I = 0, δeI : − (−1)n dφI − a1φK ∧ ωK I + 2b3φIK ∧ eK + a1b1 a2 ψK ∧ RK I − a1(a1 − b2) a2 ψN ∧ ωN K ∧ ωK I + 4b3a2 b1 ψIK ∧ eK − 2b3(a1 − b2) b1 ψKN ∧ ωI N ∧ eK + 2b3(a1 − b2) b1 ψIN ∧ ωK N ∧ eK = 0, δωIJ : − (−1)n dφIJ + a1φ[I ∧ eJ] + 2b2φ[I|K ∧ ω|J] K − a1ψ[I| ∧ T|J] + a1(a1 − b2) a2 ψK ∧ e[I| ∧ ωK |J] + a1(a1 − b2) a2 ψ[I| ∧ eK ∧ ω|J] K − 2b2ψ[I|K ∧ R|J] K + 2b3(a1 − b2) b1 ψK[I| ∧ eK ∧ e|J] = 0, δRIJ : (−1)n dψIJ − b1φIJ + a1b1 a2 φ[I| ∧ e|J] + 2b2ψK[I| ∧ ωK |J] = 0, δTI : (−1)n dψI − a2φI − a1ψK ∧ ωK I = 0, (10) 5. Conclusions and perspectives In the present work I have made generalizations for the topological ﬁeld theories in n-dimensional spacetimes that were made at [1] and with this I obtain my initial purpose. For future work, I can make a 1 + 1 decomposition for the two dimensional case, a 2 + 1 decomposition for the three dimensional case or a (n − 1) + 1 decomposition for the n dimensional case, after that I can make the hamiltonian analysis for all the existed actions and I will be able to count the degrees of freedom for my theories. I will be able to analyze particular cases and so on. References [1] V. Cuesta, M. Montesinos, M. Vel´azquez and J. D. Vergara, Topological Field theories in n-dimensional spacetimes and Cartan’s equations, Phys. Rev. D, 78, 064046, (2008). [2] S. Kobayashi and K. Nomizu, Foundations of differential geometry, Vol. 1, Interscience Publishers, New York, (1963). [3] S. Kobayashi and K. Nomizu, Foundations of differential geometry, Vol. 2, Interscience Publishers, New York, (1969). [4] G. F. Torres del Castillo, Notas sobre variedades diferenciables, Segunda edici´on, (1998). [5] A. I. Kostrikin, Introduction to Algebra, Springer, (1982). [6] V. Cuesta and M. Montesinos, Cartan’s equations deﬁne a topological ﬁeld theory of the BF type, Phys. Rev. D, 76, 104004, (2007).