Unveiling the curtain of superposition: Recent gedanken and laboratory experiments

TL;DR

This paper reviews and extends experiments on quantum superposition, including the three-boxes paradox and novel dynamic experiments, highlighting nonlocality, non-temporality, and the potential for new superposition phenomena.

Contribution

It introduces new dynamic and non-counterfactual experiments demonstrating particle disappearance and reappearance, advancing understanding of superposition and quantum nonlocality.

Findings

Dynamic experiments show particles can 'disappear' and 'reappear' during evolution.

Weak values can be self-cancelled, indicating exotic superposition states.

Nonlocality and nontemporality are fundamental to pre- and post-selected quantum systems.

Abstract

What is the true meaning of quantum superposition? Can a particle genuinely reside in several places simultaneously? These questions lie at the heart of this paper which presents an updated survey of some important stages in the evolution of the three-boxes paradox, as well as novel conclusions drawn from it. We begin with the original thought experiment of Aharonov and Vaidman, and proceed to its non-counterfactual version. The latter was recently realized by Okamoto and Takeuchi using a quantum router. We then outline a dynamic version of this experiment, where a particle is shown to "disappear" and "re-appear" during the time evolution of the system. This surprising prediction based on self-cancellation of weak values is directly related to our notion of Quantum Oblivion. Finally, we present the non-counterfactual version of this disappearing-reappearing experiment. Within the near future, this last version of the experiment is likely to be realized in the lab, proving the existence of exotic hitherto unknown forms of superposition. With the aid of Bell's theorem, we prove the inherent nonlocality and nontemporality underlying such pre- and post-selected systems, rendering anomalous weak values ontologically real.