STRUCTURE II

BOUNDARY

The world changes when the boundary changes.

Boundary is not a limit. Boundary is a generative mechanism. When boundary conditions change, geometry changes, information flow changes, and the world follows.

Studies of interfaces, limits, and encoding structures.

THEORY EVOLUTION

【2020】JHEP 03 (2021) 008

Defect extremal surface as the holographic counterpart of Island formula

ARXIVPDFDOI

TECHNICAL CORE

Geometrizing the Island formula into defect extremal surfaces.

STRUCTURAL SIGNIFICANCE

The starting point: extremal surfaces as 'defect boundaries' – boundaries as information generators.

【2021】JHEP 10 (2021) 149

Page curve from defect extremal surface and island in higher dimensions

ARXIVPDFDOI

TECHNICAL CORE

Extending defect extremal surfaces to higher-dimensional Page curves.

STRUCTURAL SIGNIFICANCE

Boundary controls the temporal evolution of information flow. Boundary shapes history.

【2022】JHEP 02 (2023) 219

JT gravity from partial reduction and defect extremal surface

ARXIVPDFDOI

TECHNICAL CORE

Partial reduction deriving defect extremal surfaces.

STRUCTURAL SIGNIFICANCE

Unified boundary structure and low-dimensional gravity. A bridge between boundary and constraint.

【2023】JHEP 07 (2024) 036

End of the world brane meets TTbar

ARXIVPDFDOI

TECHNICAL CORE

Linking EOW brane embedding with TT-bar deformation.

STRUCTURAL SIGNIFICANCE

Boundary angle as a flow parameter. Boundary as a fluid structure, not a static object.

【2024】JHEP 01 (2025) 020

Holographic boundary conformal field theory with TTbar deformation

ARXIVPDFDOI

TECHNICAL CORE

Geometric realization of TTbar-deformed BCFT.

STRUCTURAL SIGNIFICANCE

Boundary shift = spectral flow. Geometric flow = information flow. The maturation of the theory.

【2026】Preprint

Boundary flow and geometric realization in holographic TTbar-deformed BCFT

ARXIVPDF

TECHNICAL CORE

Complete geometric interpretation of boundary flow.

STRUCTURAL SIGNIFICANCE

The world is not inside the boundary; the world is generated in the flow of the boundary.