Can anti-de Sitter space smoothly become flat spacetime?

Taking the flat-space limit of anti-de Sitter (AdS) solutions reveals how boundary data in curved space maps to infinite towers of conserved charges in flat spacetime. The authors trace this connection for particles of any integer spin in any even dimension, showing that the AdS source and expectation value decompose into representations that match conformal symmetries of the celestial sphere—the sphere at infinity where physicists encode scattering data.