Waterfall stiff period can generate observable primordial gravitational waves

Abstract

A toy-model is studied, which considers two flat directions meeting at an enhanced symmetry point such that they realise the usual hybrid inflation mechanism. The kinetic term of the waterfall field features a pole at its Planckian vacuum expectation value (VEV), as with $\alpha$-attractors. Consequently, after the phase transition which terminates hybrid inflation, the waterfall field never rolls to its VEV. Instead, it drives a stiff period, where the barotropic parameter of the Universe $w\approx 1/2$ results in a peak in the spectrum of primordial gravitational waves, which will be observable by the forthcoming LISA mission as well as by Advanced LIGO.

19 pages, 3 figures, published version

References in corpus (11)

• Advanced Virgo: a 2nd generation interferometric gravitational wave detector
• Advanced LIGO
• Laser Interferometer Space Antenna
• Improved Calculation of the Primordial Gravitational Wave Spectrum in the Standard Model
• Ricci Reheating
• Hybrid cosmological attractors
• Warm Quintessential Inflation
• Curvaton reheating allows TeV Hubble scale in NO inflation
• Precision cosmology and the stiff-amplified gravitational-wave background from inflation: NANOGrav, Advanced LIGO-Virgo and the Hubble tension
• What is needed of a scalar field if it is to unify inflation and late time acceleration ?
• Effective field theory of waterfall in hybrid inflation

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• Mechanisms for producing Primordial Black Holes from Inflationary Models Beyond Fine-Tuning
• E- & T-Model Hybrid Inflation