报告题目：Hamiltonian Analysis of Gravity in 3 Dimension Spacetime under Null Coframe (在类光余标架下三维时空引力的哈密顿分析) 

报告人：　孔师碑

报告日期：7/20（三）上午 10：00 报告地点：理论室319

报告摘要：The null coframe in this work is inspired by the Newman-Penrose form in 3 dimension. Connections are treated independently. Bondi-like coordinates are used in this work. Lagrangian of the gravity is acquired from the Palatini action with a cosmological constant term. Equations about the conjugate momentums are treated as primary constraints, where only one is the first class constraint. Hamiltonian is acquired from Legendre transformation of the Lagrangian. All secondary constraints and the Lagrange multiplicative factors are acquired from Hamiltonian analysis. A new first class constraint is obtained from certain combination of some primary constraints. There is no degree of freedom left in this system. Equations of motion of the canonical variables are calculated. In the end, the above results are applied to BTZ spacetime.