Watanabe's work was later rediscovered by Yakir Aharonov, Peter Bergmann and Joel Lebowitz in 1964, who later renamed it the Two-State Vector Formalism (TSVF).
The two-state vector formalism provides a time-symmetric description of quantum mechanics, and is constructed such as to be time-reversal invariant.
[6] In view of the TSVF approach, and in order to allow information to be obtained about quantum systems that are both pre- and post-selected, Yakir Aharonov, David Albert and Lev Vaidman developed the theory of weak values.
Similarly as the de Broglie–Bohm theory, TSVF yields the same predictions as standard quantum mechanics.
[7] Lev Vaidman emphasizes that TSVF fits very well with Hugh Everett's many-worlds interpretation,[8] with the difference that initial and final conditions single out one branch of wavefunctions (our world).
[9] The two-state vector formalism has similarities with the transactional interpretation of quantum mechanics proposed by John G. Cramer in 1986, although Ruth Kastner has argued that the two interpretations (Transactional and Two-State Vector) have important differences as well.