منابع مشابه
Signature change induces compactification.
It is shown – using a FRW model with S 3 × S 6 as spatial sections and a positive cosmological constant – that classical signature change implies a new compactification mechanism. The internal scale factor is of the order Λ −1/2 , and the solutions are stable against small perturbatons. In the case of compactified S 6 , it is shown that the effective four-dimensional space-time metric has Loren...
متن کاملSignature Transition and Compactification
It is shown that a change in the signature of the space-time metric together with compactification of internal dimensions could occur in a six-dimensional cosmological model. We also show that this is due to interaction with Maxwell fields having support in the internal part of the space-time. PACS: 0.420.Gz,0.4.50+h
متن کاملCompactification, topology change and surgery theory
We study the process of compactification as a topology change. It is shown how the mediating spacetime topology, or cobordism, may be simplified through surgery. Within the causal Lorentzian approach to quantum gravity, it is shown that any topology change in dimensions ≥ 5 may be achieved via a causally continuous cobordism. This extends the known result for 4 dimensions. Therefore, there is n...
متن کاملDynamical Topology Change, Compactification and Waves in String Cosmology
Exact string solutions are presented, where moduli fields are varying with time. They provide examples where a dynamical change of the topology of space is occurring. Some other solutions give cosmological examples where some dimensions are compactified dynamically or simulate pre-big bang type scenarios. Some lessons are drawn concerning the region of validity of effective theories and how the...
متن کاملSignature Change and Clifford Algebras
Given the real Clifford algebra of a quadratic space with a given signature, we define a new product in this structure such that it simulates the Clifford product of a quadratic space with another signature different from the original one. Among the possible applications of this new product, we use it in order to write the minkowskian Dirac equation over the euclidean spacetime and to define a ...
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ژورنال
عنوان ژورنال: Physical Review D
سال: 1995
ISSN: 0556-2821
DOI: 10.1103/physrevd.52.2150