Speaker: Feiyu Deng (Institute of Theoretical Physics, Chinese Academy of Sciences)
Time: 2026-03-12 15:00-16:30
Location: 710, SIMIS
Zoom meeting ID: 872 5628 2505 Password: SIMIS
Abstract:
We study the T\bar{T} deformation of boundary conformal field theories (BCFTs) from an intrinsic field-theoretic perspective.
For BCFTs without independent boundary degrees of freedom, imposing reflective boundary conditions causes the bulk composite operator generating the T\bar{T} flow to collapse onto the physical boundary.
Using BCFT Ward identities, we show that the deformation reduces to a boundary-localized irrelevant flow governed entirely by the displacement operator, which generates normal deformations of the boundary embedding.
We then analyze two holographic constructions.
In Type A, a flat bulk geometry with a rigid cutoff surface intersects the end-of-the-world brane and produces a non-perturbative displacement of the BCFT boundary.
In Type B, the bulk geometry is asymptotically AdS and geometrically pins the boundary, forcing the displacement operator to vanish.
About Speaker:
Feiyu Deng is a postdoctoral researcher at the Institute of Theoretical Physics, Chinese Academy of Sciences.
He received his PhD in physics from Fudan University.
His research focuses on holography, boundary and defect conformal field theories, and irrelevant deformations such as T\bar{T}.
He is broadly interested in quantum gravity, black hole physics, and the interplay between quantum information and spacetime geometry.
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