Negative Mass Particles Offer a New Understanding of Quantum Interaction

The Two State-Vector Formalism of Yakir Aharonov has yielded many surprising predictions about the dynamics of a particle during the time-interval between past and future measurements. However, these intermediate states, rigorously derived from standard quantum theory, are, by definition, impossible to validate by measurement. I present an experiment where this difficulty has been overcome, and a projective ("strong") measurement probed this dynamics. An intriguing interplay between positive- and negative-mass particles is revealed, shedding new light on the "bomb-testing experiment" and further into the nature of the wave function.