Karl-Henning Rehren (born 1956 in Celle) is a German physicist who focuses on algebraic quantum field theory.
Rehren studied physics in Heidelberg, Paris and Freiburg. In Freiburg he received his PhD (advisor Klaus Pohlmeyer) in 1984. Habilitation 1991 in Berlin. Since 1997 he teaches physics in Göttingen.
In 1999 he discovered the Algebraic holography (also Rehren duality), a duality in the sense of the Holographic principle, which maps N=4 superconformal SU(N) Yang-Mills theory to an ordinary quantum field theory on AdS5. This is at least in superficial contradiction to the more well known Maldacena duality, the AdS/CFT correspondence.
In 2006 he co-authored the controversial review article Quantum Field Theory: Where We Are to be published in the book An Assessment of Current Paradigms in the Physics of Fundamental Phenomena.