Time: 10:00-12:00, Feb. 2, 2026, Beijing/Shanghai

Zoom Meeting ID: 949-559-7503

Speaker: Wendi Tan (Unviersite Libre de Bruxelles）

Abstract:

Motivated by issues in the context of asymptotically flat spacetimes at null infinity, we discuss in the simplest example of a free massless scalar field in two dimensions several subtleties that arise when setting up the canonical formulation on a single or on two intersecting null hyperplanes with a special emphasis on the infinite-dimensional global and conformal symmetries and their canonical generators, the free data, a consistent treatment of zero modes, matching conditions, and implications for quantization of massless versus massive fields.