  A combinatorial optimization problem becomes very difficult in situations
where the energy landscape is rugged, and the global minimum locates in a
narrow region of the configuration space. When using the quantum approximate
optimization algorithm (QAOA) to tackle these harder cases, we find that
difficulty mainly originates from the QAOA quantum circuit instead of the cost
function. To alleviate the issue, we selectively dropout the clauses defining
the quantum circuit while keeping the cost function intact. Due to the
combinatorial nature of the optimization problems, the dropout of clauses in
the circuit does not affect the solution. Our numerical results confirm
improvements in QAOA's performance with various types of quantum-dropout
implementation.
