60周年校庆系列讲座－－5月20日吴兆颜教授：Momentum Conservation and Nonlocalizability of ……

　　报告主题：Energy-Momentum Conservation and Nonlocalizability of Gravitational Energy in GR
　　主讲人：吴兆颜教授
　　地点：屏峰校区理学A楼报告厅
　　时间：2013年5月20日（周一）9:00-10:00
　　主办单位：理学院
　　联系电话：85290306

　　主讲人简介：
　　吴兆颜，教授，吉林大学物理系理论物理专业毕业。1982-1984美国旺尼办达大学物理系访问学者。 主要科研工作领域为量子绝热演化的几何及量子中间统计理论。

　　讲座摘要：
　　This talk is based on a general variational principle, and Noether's theorem is revisited. It is shown that the long existing pseudotensor problem of gravitational energy-momentum, is only a result of misreading Noether's theorem and mistaking different geometrical, physical objects as one and the same. As a matter of fact, all the Noether's conserved quantities in general relativity are scalars, their conservation currents are vector fields. The difficulty of non-localizability of gravitational energy-momentum, which is a direct consequence of the pseudotensor property, does not really exist. Each dynamic system (matter field plus metric field) has infinitely many so-called canonical energy-momentums, which are the conservation currents due to the coordinate shift invariance of its action, but it has only one energy-momentum of matter which appears in Einstein's field equation. It is pointed out the sum of energy-momentum 4-vector can not be defined in a curved spacetime. The law of energy conservation just holds approximately in a spacetime region which is approximately flat. Gravitational wave does not carry energy-momentum.