2024/10/11 by Walker Melton, Melton, Walker, Atul Sharma +5 · 3 citations
Mathematics · Physics and Astronomy · #Black Holes and Theoretical Physics #FOS: Physical sciences #High Energy Physics - Theory (hep-th) #Nonlinear Waves and Solitons #Spectral Theory in Mathematical Physics
paper · pdf · doi:10.48550/arxiv.2410.08853
openalex publication_date 2024/10/11 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
Analytic continuation from (3,1) signature Minkowski to (2,2) signature Klein space has emerged as a useful tool for the understanding of scattering amplitudes and flat space holography. Under this continuation, past and future null infinity merge into a single boundary (J) which is the product of a null line with a (1,1) signature torus. The Minkowskian S-matrix continues to a Kleinian S-vector which in turn may be represented by a Poincaré-invariant vacuum state |C⟩ in the Hilbert space built on J. |C ⟩ contains all information about S in a novel, repackaged form. We give an explicit construction of |C⟩ in a Lorentz/conformal basis for a free massless scalar. J separates into two halves J_± which are the asymptotic null boundaries of the regions timelike and spacelike separated from the origin. |C⟩ is shown to be a maximally entangled state in the product of the J_± Hilbert spaces.