Non-adaptive measurement-based quantum computation on IBM Q
We test the quantumness of IBM's quantum computer IBM Quantum System One in
Ehningen, Germany. We generate generalised n-qubit GHZ states and measure Bell
inequalities to investigate the n-party entanglement of the GHZ states. The
implemented Bell inequalities are derived from non-adaptive measurement-based
quantum computation (NMQC), a type of quantum computing that links the
successful computation of a non-linear function to the violation of a
multipartite Bell-inequality. The goal is to compute a multivariate Boolean
function that clearly differentiates non-local correlations from local hidden
variables (LHVs). Since it has been shown that LHVs can only compute linear
functions, whereas quantum correlations are capable of outputting every
possible Boolean function it thus serves as an indicator of multipartite
entanglement. Here, we compute various non-linear functions with NMQC on IBM's
quantum computer IBM Quantum System One and thereby demonstrate that the
presented method can be used to characterize quantum devices. We find a
violation for a maximum of seven qubits and compare our results to an existing
implementation of NMQC using photons.
Jelena Mackeprang Daniel Bhatti Stefanie Barz