Unveiling the curtain of superposition: Recent gedanken and laboratory experiments

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. Scarbo (translated to English), from Gaspard de la nuit / Aloysius Bertrand

Nonlocal Position Changes of a Photon Revealed by Quantum Routers

“…Surprisingly, we have three different predictions (see also [22,23]) for the three instants during this interval, depending on the moment 1 ( ) 0 and ( ) 0 and ( ) 1,…”

“…To simulate this evolution in our proposed photonic experiment, we would later use two beam-splitters. Surprisingly, we have three different predictions (see also [22,23]) for the three instants during this interval, depending on the moment 1…”

“…These indeed were the advances made over the years, mostly recently. Experimental settings involving strong measurements were offered to test extraordinary TSVF predictions like the "Cheshire cat" [16], the "quantum pigeonhole" [20,21] and the "disappearing and re-appearing particle" [22,23]. Also, as noted above, a protocol involving strong measurements proposed by Aharonov and Vaidman [7] was experimentally realized by Okamoto and Takeuchi [8], to be elaborated in greater detail below.…”