The Many-Worlds Interpretation of Quantum Mechanics: Current Status and Relation to Other Interpretations.
Research workshop of the Israeli Science Foundation, Tel-Aviv University, October 2022

Avshalom Elitzur

Do Parallel Worlds Leave Causal Traces in One Another?
IFM has revealed the causal potency of non-events. A detector click that did not occur leaves causal effects just because it could occur. Within MWI, this causal curiosity is offered a natural explanation. Later experiments have revealed reciprocal effects of the undetected particle on the "detector." For example, a pair of excited and ground-state atoms that apparently did not exchange a photon become entangled just because the exchange was possible. Within the Two State-Vector Formalism, such non-events are offered a one-world account in the form of double exchange of “ghost” particles, one ordinary and the other with negative mass, posing a challenge to the MWI. I compare these Many- and One-World accounts and argue in favor of the latter.