報告題目：Hamiltonian reduction for spacetimes in the 2+2 formalism   

　　報告人：Prof. Jong Hyuk Yoon Konkuk University, Korea 

　　時間安排：2016年9月9日16：30         

　　地點：近代物理所5號樓1006會議室 

　　報告摘要:  

　　I apply the Hamiltonian reduction procedure to general spacetimes of 4 dimensions in the (2+2) formalism and find privileged spacetime coordinates in which the physical Hamiltonian is expressed in terms of the conformal two metric and its conjugate momentum. Physical time is the area element of the spatial cross section of null hypersurfaces, and physical radial coordinate is defined by equipotential surfaces on a given spacelike hypersurface of constant physical time. The physical Hamiltonian is local and positive in the privileged coordinates. I present the complete set of the Hamilton's equations, and find that they coincide with the Einstein's equations written in the privileged coordinates. This shows that our Hamiltonian reduction is self-consistent and respects general covariance.