Adaptability of quantum annealing for 1-bit MIMO design to RIS phase-shift optimization

Determine whether the quantum annealing approach used for the b = 2 (1-bit) pre- and post-coding design in MIMO systems can be adapted to reconfigurable intelligent surface (RIS) phase-shift optimization, where the phase shifts are continuous and can be directly represented by rotation gates in a quantum circuit.

Background

The paper contrasts its QAOA-based framework, which handles higher-order terms and maps phase shifts to rotation gates, with earlier work that used quantum annealing for the special case b = 2. The authors argue their approach naturally extends to problems like RIS phase-shift optimization that involve continuous phase values.

They explicitly state that it is unclear whether the prior quantum annealing method can be adapted to RIS optimization, identifying a concrete unresolved question about method transferability between discrete and continuous phase settings.