Geometrical Origin of the Cosmological Constant

Abstract

We show that the description of the space-time of general relativity as a diagonal four dimensional submanifold immersed in an eight dimensional hypercomplex manifold, in torsionless case, leads to a geometrical origin of the cosmological constant. The cosmological constant appears naturally in the new field equations and its expression is given as the norm of a four-vector $U$, i.e., $\Lambda =6g_{\mu \nu }{U}^{\mu }{U}^{\nu }$ and where U can be determined from the Bianchi identities. Consequently, the cosmological constant is space-time dependent, a Lorentz invariant scalar, and may be positive, negative or null. The resulting energy momentum tensor of the dark energy depends on the cosmological constant and its first derivative with respect to the metric. As an application, we obtain the spherical solution for the field equations. In cosmology, the modified Friedmann equations are proposed and a condition on $\Lambda$ for an accelerating universe is deduced. For a particular case of the vector $U$, we find a decaying cosmological constant $\Lambda \propto a(t{)}^{-6\alpha }$.

15 pages, LaTeX, Published version, General Relativity and Gravitation (2012), Online First

References in corpus (8)

• Pseudo-complex General Relativity
• Area metric gravity and accelerating cosmology
• Gravitoelectromagnetism in a complex Clifford algebra
• Pseudo-Complex Field Theory
• The Robertson-Walker Metric in a Pseudo-Complex General Relativity
• Radiation-dominated area metric cosmology
• Hermitian Gravity and Cosmology
• Gravity in Complex Hermitian Space-Time

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