Non-Gaussian and nonscale-invariant perturbations from tachyonic preheating in hybrid inflation

被引:94
作者
Barnaby, Neil [1 ]
Cline, James M. [1 ]
机构
[1] McGill Univ, Dept Phys, Montreal, PQ H3A 2T8, Canada
来源
PHYSICAL REVIEW D | 2006年 / 73卷 / 10期
关键词
D O I
10.1103/PhysRevD.73.106012
中图分类号
P1 [天文学];
学科分类号
0704 ;
摘要
We show that in hybrid inflation it is possible to generate large second-order perturbations in the cosmic microwave background due to the instability of the tachyonic field during preheating. We carefully calculate this effect from the tachyon contribution to the gauge-invariant curvature perturbation, clarifying some confusion in the literature concerning nonlocal terms in the tachyon curvature perturbation; we show explicitly that such terms are absent. We quantitatively compute the non-Gaussianity generated by the tachyon field during the preheating phase and translate the experimental constraints on the nonlinearity parameter f(NL) into constraints on the parameters of the model. We also show that nonscale-invariant second-order perturbations from the tachyon field with spectral index n=4 can become larger than the inflaton-generated first-order perturbations, leading to stronger constraints than those coming from non-Gaussianity. The width of the excluded region in terms of the logarithm of the dimensionless coupling g, grows linearly with the log of the ratio of the Planck mass to the tachyon VEV, log(M-p/v); hence very large regions are ruled out if the inflationary scale v is small. We apply these results to string-theoretic brane-antibrane inflation, and find a stringent upper bound on the string coupling, g(s)< 10(-4.5).
引用
收藏
页数:29
相关论文
共 97 条
[1]  
ABBOTT LF, BRXTH174
[2]   Gauge-invariant second-order perturbations and non-Gaussianity from inflation [J].
Acquaviva, V ;
Bartolo, N ;
Matarrese, S ;
Riotto, A .
NUCLEAR PHYSICS B, 2003, 667 (1-2) :119-148
[3]   NON-GAUSSIAN DENSITY PERTURBATIONS IN INFLATIONARY COSMOLOGIES [J].
ALLEN, TJ ;
GRINSTEIN, B ;
WISE, MB .
PHYSICS LETTERS B, 1987, 197 (1-2) :66-70
[4]  
[Anonymous], HEPPH0210162
[5]   Tachyonic preheating using 2PI-1/N dynamics and the classical approximation [J].
Arrizabalaga, A ;
Smit, J ;
Tranberg, A .
JOURNAL OF HIGH ENERGY PHYSICS, 2004, (10) :317-349
[6]   False vacuum decay after inflation [J].
Asaka, T ;
Buchmüller, W ;
Covi, L .
PHYSICS LETTERS B, 2001, 510 (1-4) :271-276
[7]  
Barnaby N, 2005, J HIGH ENERGY PHYS
[8]  
Barnaby N, 2004, J HIGH ENERGY PHYS
[9]  
BARNABY N, UNPUB
[10]   Non-Gaussianity from inflation: theory and observations [J].
Bartolo, N ;
Komatsu, E ;
Matarrese, S ;
Riotto, A .
PHYSICS REPORTS-REVIEW SECTION OF PHYSICS LETTERS, 2004, 402 (3-4) :103-266