Singular Cosmological Instantons Made Regular
نویسنده
چکیده
The singularity present in cosmological instantons of the Hawking-Turok type is resolved by a conformal transformation, where the conformal factor has a linear zero of codimension one. We show that if the underlying regular manifold is taken to have the topology of RP 4, and the conformal factor is taken to be a twisted field so that the zero is enforced, then one obtains a genuine saddle point of the Einstein-scalar theory in which the conformal zero is located on a minimal volume noncontractible RP 3 submanifold. For instantons with two singularities, the corresponding topology is that of a cylinder S3 × [0, 1] with D = 4 analogues of ‘cross-caps’ at each of the endpoints.
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