Sharing EPR steering between sequential pairs of observers

Abstract

The recycling of quantum correlations has attracted widespread attention both theoretically and experimentally. Previous works show that bilateral sharing of nonlocality is impossible under mild measurement strategy and 2-qubit entangled state can be used to witness entanglement arbitrary many times by sequential and independent pairs of observers. However, less is known about the bilateral sharing of EPR steering yet. Here, we aim at investigating the EPR steering sharing between sequential pairs of observers. We show that an unbounded number of sequential Alice-Bob pairs can share the EPR steering as long as the initially shared state is an entangled
two-qubit pure state. The claim is also true for particular class of mixed entangled states.

Quantum Correlation Resource Recycling via Sequential Measurements: Theoretical Models and Optical Experiments

“…In addition, they prove that the above conclusion also applies in cases where each Bob does not know its position in the sequence. Recently, a study [66] investigating the sharing of EPR steering by two-sided sequences shows that, for the initial shared state of a two-qubit entangled pure state, there are unbounded measurement sequences from both sides that can generate EPR steering between multiple independent observers. This conclusion also applies to a specific class of mixed entangled states.…”