arXiv · 0708.3950
We consider the noncommutative minisuperspace classical and quantum cosmologies.
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Aleksandar Zejak, Branko Dragovich. 2007-08-29. Noncommutative Minisuperspace Cosmology. https://arxiv.org/abs/0708.3950
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Coleman--De Luccia tunneling can exhibit an infinite tower of rapidly oscillating negative modes, complicating the semiclassical evaluation of the path integral. We show that this tower does not represent infinitely many bounce-specific instabilities, but instead is tied to a single underlying gravitational conformal sector. This sector is exposed in two different ways: by a large scalar gradient near the bubble wall and by the turning point of a compact Euclidean geometry. The corresponding conformal sector is already present in fluctuations about the false vacuum. Treating the bounce and the false vacuum in the same well-defined gauge and with a common regulator, we find that their high-frequency negative spectra approach one another. The ultraviolet tower therefore cancels from the relative negative-mode count, leaving a single bounce-specific negative mode. This finite-backreaction spectral cancellation provides a corresponding picture of the result obtained in the small-backreaction limit.
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