Quantum correlation generation capability of experimental processes
Einstein-Podolsky-Rosen (EPR) steering and Bell nonlocality illustrate two
different kinds of correlations predicted by quantum mechanics. They not only
motivate the exploration of the foundation of quantum mechanics, but also serve
as important resources for quantum-information processing in the presence of
untrusted measurement apparatuses. Herein, we introduce a method for
characterizing the creation of EPR steering and Bell nonlocality for dynamical
processes in experiments. We show that the capability of an experimental
process to create quantum correlations can be quantified and identified simply
by preparing separable states as test inputs of the process and then performing
local measurements on single qubits of the corresponding outputs. This finding
enables the construction of objective benchmarks for the two-qubit controlled
operations used to perform universal quantum computation. We demonstrate this
utility by examining the experimental capability of creating quantum
correlations with the controlled-phase operations on the IBM Quantum Experience
and Amazon Braket Rigetti superconducting quantum computers. The results show
that our method provides a useful diagnostic tool for evaluating the primitive
operations of nonclassical correlation creation in noisy intermediate scale
quantum devices.
Wei-Hao Huang Shih-Hsuan Chen Chun-Hao Chang Tzu-Liang Hsu Kuan-Jou Wang Che-Ming Li