Volume 4, Issue 1, pages 142-146
Louis Marchildon is Professor of Physics (Emeritus) at Université du Québec à Trois-Rivières (UQTR). He obtained his B.Sc. and M.Sc. from UQTR, and his Ph.D. from Yale University in 1978. After postdoctoral work at Institut des hautes études scientifiques (France), he returned to UQTR where, in addition to research in relativity, he collaborated with a group investigating dielectric properties of materials. His book Quantum Mechanics: From Basic Principles to Numerical Methods and Applications was published by Springer in 2002. He served as President of the Canadian Association of Physicists in 2007-2008. He has now been working on quantum foundations for more than 15 years, and is also interested in science popularization.
Kastner (this issue) and Kastner and Cramer (arXiv:1711.04501) argue that the Relativistic Transactional Interpretation (RTI) of quantum mechanics provides a clear definition of absorbers and a solution to the measurement problem. I briefly examine how RTI stands with respect to unitarity in quantum mechanics. I then argue that a specific proposal to locate the origin of nonunitarity is flawed, at least in its present form.