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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. |

Subjects: Physics >> General Physics: Statistical and Quantum Mechanics, Quantum Information, etc.

We investigate constraints on Lorentz invariance violation in the neutrino sector from a joint analysis of big bang nucleosynthesis and the cosmic microwave background. The e#11;ect of Lorentz invariance violation during the epoch of big bang nucleosynthesis changes the predicted helium-4 abundance, which in uences the power spectrum of the cosmic microwave background at there combination epoch. In combination with the latest measurement of the primordial helium-4abundance, the Planck 2015 data of the cosmic microwave background anisotropies give a strong constraint on the deformation parameter since adding the primordial helium measurement breaks the degeneracy between the deformation parameter and the physical dark matter density. |

Dodging the cosmic curvature toprobe the constancy of the speed oflight

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

We develop a new model-independent method to probe the constancy of the speed of light c. In our method, the degeneracy between the cosmic curvature and the speed of light can be eliminated, which makes the test more natural and general. Combining the independent observations of Hubble parameter H(z) and luminosity distance dL(z), we use the model-independent smoothing technique, Gaussian processes, to reconstruct them and then detect variation of the speed of light. We find no signal of deviation from the present value of the speed of light c0. Moreover, to demonstrate the improvement in probing the constancy of the speed of light from future experiments, we produce a series of simulated data. The Dark Energy Survey will be able to detect #1;c/c0 #24; 1% at #24; 1.5σ confidencelevel and #1;c/c0 #24; 2% at #24; 3σ confidence level. If the errors are reduced to one-tenth of the expected DES ones, it can detect a #1;c/c0 #24; 0.1% variation at #24; 2σ confidence level. |

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