Measurement and collapse within the two-state vector formalism

Abstract

The notion of collapse is discussed and refined within the two-state vector formalism (TSVF). We show how a definite result of a measurement can be fully determined when considering specific forward- and backward-evolving quantum states. Moreover, we show how macroscopic time reversibility is attained, at the level of a single branch of the wavefunction, when several conditions regarding the final state and dynamics are met, a property for which we coin the term “classical robustness under time-reversal”. These entail a renewed perspective on the measurement problem, the Born rule and the many-worlds interpretation.