Theory Seminar
KEK 素粒子原子核研究所・理論セミナー
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TITLE： |
Quantum Gravity from Noncommuative Gauge Theory |
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（英語/in English) |
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SPEAKER： |
Dr. Hyun Seok Yang (KIAS) |
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DATE： |
October 15
(Thu.) 13:30- |
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PLACE: |
KEK Bldg.4, 3F Room 345 |
（ABSTRACT）
We show that the first principle to realize Einstein gravity from a quantum field theory would be the geometrization of gauge fields based on the symplectic and noncomm utative (NC) geometry. In particular, the Darboux theorem in symplectic geometry admits a novel form of the equivalence principle such that there always exists a coordinate transformation to locally eliminate the electromagnetic force. As a result, the electromagnetism in NC spacetime can be regarded as a theory of gravity. Remarkably the emergent gravity reveals a noble picture about the origin of spacetime, dubbed as emergent spacetime. In particular, the emergent gravity naturally explains the dynamical origin of flat spacetime, which is absent in Einstein gravity: A flat spacetime is not free gratis but a result of Planck energy condensation in a vacuum. This emergent spacetime picture turns out to be essential to resolve the cosmological constant problem, to understand the nature of dark energy and to explain why gravity is so weak compared to other forces.