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# Second Quantization of the Dirac Field: Normal Modes in the Robertson–Walker Space-Time

International Journal of Theoretical Physics (Impact Factor: 1.19). 01/1998; 37(3):995-1009.

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**ABSTRACT:**The spinor formulation of the massive spin-1 equation is considered in the general Robertson-Walker space-time. The corresponding differential equations are separated by an elementary separation method that has the advantage of being a simple extension of the one previously used in the massless case. The independent separated angular and radial equations are shown to reduce to those of the massless case and are explicitly integrated. Two separated time functions satisfying two coupled differential equations are necessary to describe the time dependence. Explicit solutions of the time equations are given in the massless case and for some meaningful laws of universe expansion in the massive case.Il Nuovo Cimento B 01/2005; 120. -
##### Article: The Einstein-Dirac Equation in Robertson-Walker Space-Time Does Not Admit Standard Solutions

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**ABSTRACT:**The Einstein-Dirac equation is considered in the Robertson-Walker space-time. Solutions of the equation are looked for in the class of standard solutions of the Dirac equation. It is shown that the Einstein-Dirac equation does not have standard solutions for both massive and massless Dirac field. Also superpositions of massive standard solutions are not solutions of the Einstein-Dirac equation. The result, that is briefly commented, is coherent and complementary to other existing results.International Journal of Theoretical Physics 08/2009; 48(8):2305-2310. · 1.19 Impact Factor - [Show abstract] [Hide abstract]

**ABSTRACT:**The study of the field equation of arbitrary spin in Robertson-Walker space-time, previously separated by variable separation, is completed. The integration of the separated radial equations is performed in an uni-fied way with respect to the curvature parameter. Through a sequence of transformations on the variable and of the radial function, the radial equation is reported to the Heun's differential equation. The solution of the Heun's equation however does fall into the class of known func-tions such as the hypergeometric, the polynomial, the polynomial-like function, only exceptionally. Moreover the Heun's differential operator admits of a factorization, a property that would simplify the integration, only for special values of the parameters.Adv. Studies Theor. Phys. 01/2010; 4203030(02).

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