MG14 - Talk detail |
Participant |
Xue, She-Sheng | |||||||
Institution |
ICRANet - Piazzale della Repubblica, - Pescara - Abrruzo - Italy | |||||||
Session |
SF1-2 |
Accepted |
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Oral abstract |
Title |
Gravitational and electricenergies in gravitational collapses | |||||
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Abstract |
We discuss in gravitational collapses how gravitational energy is converted to both kinetic and electric energies in form of electron-positron-photon plasma. It is shown that (i) averaged kinetic and electric energies are the same order, about an half of gravitational energy of stellar cores in collapse; (ii) caused by radiating and rebuilding electric energy, gravitational collapse undergoes a sequence of ``on and off'' hopping steps in the microscopic Compton scale, and it is slowed down as kinetic energy is reduced and collapsing time becomes longer. |
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Session |
DE1 |
Accepted |
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Oral abstract |
Title |
How universe evolves with cosmological and gravitational constants (Nucl. Phys. B in press) | |||||
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Abstract |
We study a regularized and quantized Einstein-Cartan gravitational field theory and its domains of ultraviolet-unstable fixed point $g_{\rm ir}\gtrsim 0$ and ultraviolet-stable fixed point $g_{\rm uv}\approx 4/3$ of the gravitational gauge coupling $g=(4/3)G/G_{\rm Newton}$. Because the fundamental operators of quantum gravitational field theory are dimension-2 area operators, the cosmological constant is inversely proportional to the squared correlation length $\Lambda\propto \xi^{-2}$. The correlation length $\xi$ characterizes an infrared size of a causally correlate patch of the universe. The cosmological constant $\Lambda$ and the gravitational constant $G$ are related by a generalized Bianchi identity. As the basic space-time cutoff $\tilde\ell$ decreases and approaches to the Planck length $\ell_{\rm pl}$, the universe undergoes inflation in the domain of the ultraviolet-unstable fixed point $g_{\rm ir}$, then evolves to the low-redshift universe in the domain of ultraviolet-stable fixed point $g_{\rm uv}$. We give the quantitative description of the low-redshift universe in the scaling-invariant domain of the ultraviolet-stable fixed point $g_{\rm uv}$, and its deviation from the $\Lambda$CDM can be examined by low-redshift $(z\lesssim 1)$ cosmological observations, such as supernova Type Ia. |
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Pdf file |
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