An Experimental Proposal to Study Collapse of the Wave Function in Traveling‐Wave Parametric Amplifiers

Abstract

During the process of measurement, quantum signals are amplified to human proportions. The question arises whether this amplification stage is responsible for the reduction of the state vector (also known as collapse of the wave function) during measurement. The cover image shows an artist’s impression of the experiment proposed by Tjerk H. Oosterkamp and co‐workers (article number http://doi.wiley.com/10.1002/pssb.202000567) to test this hypothesis. A single photon, indicated with sinusoids with a well‐determined amplitude, but unknown phase, is amplified within an interferometer. At some gain of the amplifiers the state might collapse unto a state with a well‐defined phase. The authors study how they can observe whether a collapse took place within the interferometer, or not.