Measuring Quantum Superpositions

Alejandro Díaz-Caro, Gilles Dowek B

Yuan Xu

In this study, we use a decoherence-based measure of interference to quantify the effective degree of quantum superposition. We show that a type of measure of the effective degree of quantum superposition can be considered from a unified theoretical framework. We use three decoherence processes to define a corresponding decoherence-based measure of quantum superposition, including amplitude damping, phase damping and quantum Brownian motion. With these definitions, we compare the effective degree of quantum superposition achieved for the different experiments. We also investigate the effective degree of quantum superposition prepared from a mixed state through the reservoir engineering technique.

Mark P. Silverman

Andrew Knight

I show in this paper why the universality of quantum mechanics at all scales, which implies the possibility of Schrodinger's Cat and Wigner's Friend thought experiments, cannot be experimentally confirmed, and why macroscopic superpositions in general cannot be observed or measured, even in principle. Through the relativity of quantum superposition and the transitivity of correlation, it is shown that from the perspective of an object that is in quantum superposition relative to a macroscopic measuring device and observer, the observer is already sufficiently well correlated to the measuring device that once the object correlates to the measuring device, there is no time period in which the observer can perform an appropriate interference experiment to show that the measuring device is in a superposition.

Belal Ehsan Baaquie

Giacomo Mauro D’Ariano