Testing Bell's inequality with one-party weak measurements

摘要

Bell's theorem is one of the most profound scientific discoveries ever made, namely the one which establishes a departure of the nondeterministic quantum mechanical predictions from our local realistic view of the world. In essence, based on Einstein's locality conditions, the theorem settles an experimentally verifiable constraint (Bell's inequality) on the statistical correlations between the observables of spatially separated pairs of entangled particles. Here, based on the notion of sequential weak measurements, we propose a framework to test Bell's inequality in a bipartite system with only local operations made by one of the parties. This novel scenario represents a great simplification of the problem, in the sense that only one of the particles of an entangled pair is required to be manipulated and detected. The importance of the use of pointer states endowed with orbital angular momentum in the present case is also demonstrated .