Heinz-Dieter Zeh (German: [tseː]; 8 May 1932 – 15 April 2018), usually referred to as H. Dieter Zeh, was a professor (later professor emeritus) of the University of Heidelberg and theoretical physicist.

[1] Zeh was born in Braunschweig and studied physics at the Technical University of Braunschweig and nuclear physics at the University of Heidelberg under J. Hans D. Jensen.

At Heidelberg, he also investigated alpha particle formation in nuclei with Hans-Jörg Mang and Zeh investigated the topic for his PhD thesis under Mang.

[1][2] Zeh's research revolves around the fundamental problems of quantum mechanics since the 1960s, in particular with Hugh Everett III's many-worlds interpretation.

Zeh was one of the developers of the many-minds interpretation of quantum mechanics[3] and the discoverer of decoherence, first described in his seminal 1970 paper.