A Final Boundary Condition: Several Implications for the Universe

Abstract

In classical mechanics, only the initial state of the system is needed to determine its time evolution. Additional information on the final state is either redundant or inconsistent. In quantum mechanics, however, the initial state does not convey all measurements’ outcomes. Only when augmented with a final quantum state, which can be understood as propagating backwards in time, a richer, more complete picture of quantum reality is portrayed. This time-symmetric view leads to a subtle kind of a local hidden-variables theory, where true collapse never occurs, yet can be effectively observed. Moreover, the Born rule and the borderline between classical and quantum systems can be derived from, respectively, the requirements of stability and “macroscopic robustness under time-reversal.’’ The significant role of macroscopic systems in amplifying and recording quantum outcomes then directly follows. Some possible cosmological consequences of this construction are discussed, especially those related to the breakdown of the “Pigeonhole principle” and our on-going work on the concept of “Quantum Holism”. The talk will be partially based on: 1. Y. Aharonov, E. Cohen, E. Gruss, T. Landsberger, Quantum Stud.: Math. Found. 1 (2014) 133-146. 2. Y. Aharonov, E. Cohen, A.C. Elitzur, Ann. Phys. 355 (2015) 258-268. 3. Y. Aharonov, E. Cohen, to be published in “Quantum Nonlocality and Reality”, M. Bell and S. Gao (Eds.), Cambridge University Press, arXiv:1504.03797. 4. E. Cohen, Y. Aharonov, to be published in “Quantum Structural Studies: Classical Emergence from the Quantum Level”, R.E. Kastner, J. Jeknic-Dugic, G. Jaroszkiewicz (Eds.), World Scientific Publishing Co., arXiv:1602.05083.