Revealing hidden quantum steerability using local filtering operations

Abstract

Nonlocal quantum correlation is at the heart of bizarre nature of quantum physics. While there are various classes of nonlocal quantum correlation, steerability of a quantum state by local measurements provides unique operational features. Here, we theoretically and experimentally investigate the hidden quantum steerability. In particular, we find that there are initially unsteerable states which can reveal the steerability by using local filters on individual quantum systems. It is remarkable that a certain set of local filters are more effective on revealing steerability than Bell nonlocality whereas there exists another set of filters that is more effective on revealing Bell nonlocality than steerability. Finally, we present a counter-intuitive result that mixed states originating from non-maximally pure entangled states can have hidden steerability while the mixed state from a maximally pure entangled state fails to show steerability.