2025/11/24 by Avik Banerjee, Banerjee, Avik, Tanay Kibe +5
Physics and Astronomy · #Black Holes and Theoretical Physics #Quantum many-body systems #Pulsars and Gravitational Waves Research
paper · pdf · doi:10.1007/jhep07(2026)118
A bstract General solutions of a gravitational junction between two copies of a three-dimensional Einstein manifold M <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mi>M</mml:mi> </mml:math> correspond to the solutions of the non-linear Nambu-Goto equation for a string in M <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mi>M</mml:mi> </mml:math> . We show that, for the junctions in three-dimensional anti-de Sitter spacetimes constituted by tensile strings, which are dual to interfaces between thermal states in conformal field theories, the solutions of the Nambu-Goto equation describing the junction correspond to wave-packets, which are perfectly reflected at the interface to future null infinity without shape distortion when incident from past null infinity. These wavepackets are realized by half-sided conformal transformations and affect the expectation value of the displacement operator. We further show that the entanglement entropy of an interval straddling the interface deciphers the stringy modes of the dual junction even in the tensionless limit. We also demonstrate that the strong sub-additivity of entanglement entropy is satisfied and is saturated for symmetric intervals generally.