Christopher Isham

Christopher Isham (; born 28 April 1944), usually cited as Chris J. Isham, is a theoretical physicist at Imperial College London.

Research Isham's main research interests are quantum gravity and foundational studies in quantum theory. He was the inventor of an approach to temporal quantum logic called the HPO formalism, and has worked on loop quantum gravity and quantum geometrodynamics. Together with other physicists, such as John C. Baez, Isham is known as a proponent of the utility of category theory in theoretical physics. In recent years, since at least 1997, he has been working on a new approach to quantum theory based on topos theory.

He is the author of Modern differential geometry for physicists, first published in 1989.

Isham has appeared in several NOVA television programmes as well as a film about Stephen Hawking. Physicist Paul Davies has described Isham as "Britain's greatest quantum gravity expert". As a practising Christian, Isham has also written about the relationships among philosophy, theology, and physics.

Awards 2011: Dirac Medal of the Institute of Physics for his works on quantum gravity.