Evaluation of Parameterized Quantum Circuits with Cross-Resonance
  Pulse-Driven Entanglers
Variational Quantum Algorithms (VQAs) have emerged as a powerful class of
algorithms that is highly suitable for noisy quantum devices. Therefore,
investigating their design has become key in quantum computing research.
Previous works have shown that choosing an effective parameterized quantum
circuit (PQC) or ansatz for VQAs is crucial to their overall performance,
especially on near-term devices. In this paper, we utilize pulse-level access
to quantum machines and our understanding of their two-qubit interactions to
optimize the design of two-qubit entanglers in a manner suitable for VQAs. Our
analysis results show that pulse-optimized ansatze reduce state preparation
times by more than half, maintain expressibility relative to standard PQCs, and
are more trainable through local cost function analysis. Our algorithm
performance results show that in three cases, our PQC configuration outperforms
the base implementation. Our algorithm performance results, executed on IBM
Quantum hardware, demonstrate that our pulse-optimized PQC configurations are
more capable of solving MaxCut and Chemistry problems compared to a standard
configuration.
Mohannad Ibrahim Hamed Mohammadbagherpoor Cynthia Rios Nicholas T. Bronn Gregory T. Byrd