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.