时间：4月24日（周五）14:30-15:30

地点：勤园20-520

报告摘要：

This presentation provides a comprehensive bridge between the symplectic formulation of classical mechanics and the covariant phase space formalism for field theories, with particular emphasis on gauge theories and general relativity.

Key topics covered:

1.Symplectic foundations of classical Hamiltonian mechanics: configuration space, phase space, canonical symplectic structure, Poisson brackets, and Noether's theorem in phase space.

2.Covariant phase space construction for field theories: the space of solutions as phase space, symplectic structure from Lagrangian boundary terms, and the relation to the conventional $3+1$ decomposition.

3.Lee-Wald-Iyer formalism for surface charges in gauge theories: systematic derivation starting from the first variation of the Lagrangian, through Noether identities, to the definition of symplectic current and surface charge density.

The unifying theme is the geometric perspective: symplectic structures govern dynamics and conservation laws, both in finite-dimensional particle mechanics and in infinite-dimensional field theory.

报告人简介：

徐立昕，理学博士，大连理工大学教授，中国物理学会引力与相对论天体物理分会理事，在统一暗物质暗能量模型、暗能量模型、性质与修改引力模型的数据拟合和理论研究、宇宙运动学、暗物质与暗能量相互作用以及暗物质的状态方程等领域开展了一系列的研究工作。