Experimental assessment of physical realism in a quantum-controlled device

Abstract

Bohr’s complementarity principle has been challenged by quantum delayed-choice experiments wherein quantum systems are claimed to behave neither as wave nor as a particle, but in an intermediary way. However, this conclusion has been supported by retro-inference and with no direct link with the system quantum state. Here, we consider a framework that employs an operational criterion of physical reality to diagnosis the system ontology directly from the quantum state at each instant of time. We show that, in disparity with previous proposals, our setup ensures a formal link between the output visibility and elements of reality within the interferometer. An experimental proof-of-principle is provided for a two-spin-1/2 system in an interferometric setup implemented in a nuclear magnetic resonance platform. We discuss how our results validate, to a great extent, Bohr’s original formulation of the complementarity principle and unveil morphing reality states.

Complementarity relations of a delayed-choice quantum eraser in a quantum circuit

“…On the other hand, the work of [34] defines the elements of physical reality of being a wave or a particle for the morphing states in terms of contextual realism, and shows that Bohr's original complementarity principle remains valid in a quantum-controlled experiment where physical reality of the morphing state is defined at each instant of time. The elements of physical reality defined in [34] bear sound ontological meanings, but they seems to be counterfactual in nature (i.e., not empirically measurable). In our opinion, whether and how the complementarity principle should be revised remains a question open to further scrutiny.…”

A linguagem, a epistemologia e o ensino conceitual da dualidade onda-partícula

“…É interessante observar que, como formulado por Bohr, o princípio da complementaridade não conduz à contradição lógica [1]. O princípio de complementaridade de Bohr vem sendo escrutinado, tanto teoricamente [20] quanto em experimentos quânticos de espectroscopia [21], em arranjos de escolha retardada [22] e de realidade controlada [23]. Os resultados dos experimentos de escolha retardada sugerem que os sistemas quânticos podem se comportar não somente como onda ou como partícula, mas de maneira intermediária, revelando uma mudança monótona e contínua entre o comportamento de onda (nitidez do padrão de interferência) e o comportamento de partícula (borrão de marcas pontuais dispersas).…”

Considerations on the Relativity of Quantum Irrealism

“…In search for a notion of realism fundamentally disconnected from any locality hypothesis, Bilobran and Angelo introduced both a criterion of realism and a quantifier of quantum irrealism (the antithesis of realism) [ 12 ]. Their framework has recently been experimentally tested in a nuclear magnetic resonance platform and Bohr’s idea that one cannot find simultaneous elements of reality within the same setting has been confirmed [ 13 ]. In a slightly different vein but still related to realism, the Wigner friend thought experiment [ 14 ], arguably the most stripped-down statement of the measurement problem, has been revisited.…”