Experimental verification of multidimensional quantum steering

TL;DR

This paper experimentally verifies two types of quantum steering, EPR and single-system, in systems up to 16 dimensions, demonstrating their increasing steerability with dimension and potential for quantum information applications.

Contribution

It introduces a simple experimental method to certify multidimensional quantum steering, extending verification to higher-dimensional systems up to d=16.

Findings

Verified EPR steering of polarization-entangled pairs

Verified single-system (temporal) steering of single photons

Witness ratios increase with system dimension d

Abstract

Quantum steering enables one party to communicate with another remote party even if the sender is untrusted. Such characteristics of quantum systems not only provide direct applications to quantum information science, but are also conceptually important for distinguishing between quantum and classical resources. While concrete illustrations of steering have been shown in several experiments, quantum steering has not been certified for higher dimensional systems. Here, we introduce a simple method to experimentally certify two different kinds of quantum steering: Einstein-Podolsky-Rosen (EPR) steering and single-system (SS) steering (i.e., temporal steering), for dimensionality (d) up to d=16. The former reveals the steerability among bipartite systems, whereas the latter manifests itself in single quantum objects. We use multidimensional steering witnesses to verify EPR steering of polarization-entangled pairs and SS steering of single photons. The ratios between the measured witnesses and the maximum values achieved by classical mimicries are observed to increase with $d$ for both EPR and SS steering. The designed scenario offers a new method to study further the genuine multipartite steering of large dimensionality and potential uses in quantum information processing.