Quantum steering

Abstract

In his 1936 paper, ``Probability relations between separated systems,'' Schr\"odinger analyzed the quantum steering effect, showing that measurements on one part of an entangled quantum system can result in the state of the other part being ``steered'' to any state vector consistent with the original joint state. This result, which was meant to sharpen and make more precise the argument of Einstein, Podolsky, and Rosen, lay invisible in plain sight for more than 70 years. This review discusses the many extensions and generalizations to steering that have been uncovered since the ``rediscovery'' of Schr\"odinger's work.