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The Gravitational-Wave Physics

Rong-Gen Cai; Zhoujian Cao; Zong-Kuan Guo; Shao-Jiang Wang; Tao YangSubjects: Physics >> General Physics: Statistical and Quantum Mechanics, Quantum Information, etc.

The direct detection of gravitational wave by Laser Interferometer Gravitational-Wave Observatory indicates the coming of the era of gravitational-wave astronomy and gravitational-wave cosmology. It is expected that more and more gravitational-wave events will be detected by currently existing and planned gravitational-wave detectors. The gravitational waves open a new window to explore the Universe and various mysteries will be disclosed through the gravitational-wave detection, combined with other cosmological probes. The gravitational-wave physics is not only related to gravitation theory, but also is closely tied to fundamental physics, cosmology and astrophysics. In this review article, three kinds of sources of gravitational waves and relevant physics will be discussed, namely gravitational waves produced during the inflation and preheating phases of the Universe,the gravitational waves produced during the first-order phase transition as the Universe cools down and the gravitational waves from the three phases: inspiral, merger and ringdown of a compact binary system, respectively. We will also discuss the gravitational waves as a standard siren to explore the evolution of the Universe. |

Higgs in ation in Gauss-Bonnet braneworld

Rong-Gen Cai; Zong-Kuan Guo; Shao-Jiang WangSubjects: Physics >> General Physics: Statistical and Quantum Mechanics, Quantum Information, etc.

The measured masses of the Higgs boson and top quark indicate that the e#11;ective potential of the standard model either develops an unstable electroweak vacuum or stands stable all the way up to the Planck scale. In the latter case in which the top quark mass is about 2#27; below its present central value, the Higgs boson can be the inaton with the help of a large nonminimal coupling to curvature in four dimensions. We propose a scenario in which the Higgs boson can be the in aton in a#12;ve-dimensional Gauss-Bonnet braneworld model to solve both the unitarity and stability problems which usually plague Higgs ination. We #12;nd that in order for Higgs ination to happen successfully in the Gauss-Bonnet regime, the extra dimension scale must appear roughly in the range between the TeV scale and the instability scale of standard model. At the tree level, our model can give rise to a naturally small nonminimal coupling #24; #24; O(1) for the Higgs quartic coupling #21; #24; O(0:1) if the extra dimension scale lies at the TeV scale. At the loop level, the in ationary predictions at the treelevel are preserved. Our model can be confronted with future experiments and observations fromboth particle physics and cosmology. |

Reheating phase diagram for single- eld slow-roll in ationary models

Rong-Gen Cai; Zong-Kuan Guo; Shao-Jiang WangSubjects: Physics >> General Physics: Statistical and Quantum Mechanics, Quantum Information, etc.

We investigate the in uence on the in ationary predictions from the reheating processes char-acterized by the e-folding number Nreh and the e ective equation-of-state parameter wreh during the reheating phase. For the rst time, reheating processes can be constrained in the Nreh wreh plane from Planck 2015. We nd that for Higgs in ation with a nonminimal coupling to gravity, the predictions are insensitive to the reheating phase for current CMB measurements. We also nd that the spontaneously broken SUSY in ation and axion monodromy in ation with 2=3 potential, which with instantaneous reheating lie outside or at the edge of the 95% con dence region in the ns r plane from Planck 2015 TT,TE,EE+lowP, can well t the data with the help of reheating processes. Future CMB experiments would put strong constraints on reheating processes. |

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