Trans-Planckian physics and the spectrum of fluctuations in a bouncing universe -: art. no. 083514

被引:37
作者
Brandenberger, RH [1 ]
Jorás, SE
Martin, J
机构
[1] Brown Univ, Dept Phys, Providence, RI 02912 USA
[2] Inst Astrophys Paris, F-75014 Paris, France
关键词
D O I
10.1103/PhysRevD.66.083514
中图分类号
P1 [天文学];
学科分类号
0704 ;
摘要
In this paper, we calculate the spectrum of scalar field fluctuations in a bouncing, asymptotically flat universe, and investigate the dependence of the result on changes in the physics on length scales shorter than the Planck length which are introduced via modifications of the dispersion relation. In this model, there are no ambiguities concerning the choice of the initial vacuum state. We study an example in which the final spectrum of fluctuations depends sensitively on the modifications of the dispersion relation without needing to invoke complex frequencies. Changes in the amplitude and in the spectral index are possible, in addition to modulations of the spectrum. This strengthens the conclusions of previous work in which the spectrum of cosmological perturbations in expanding inflationary cosmologies was studied, and it was found that, for dispersion relations for which the evolution is not adiabatic, the predictions obtained for the spectrum of fluctuations are not robust towards changes in the dispersion relation.
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页数:9
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