Avoiding convergence stagnation in a quantum circuit evolutionary framework through an adaptive cost function

Abstract

Binary optimization problems are emerging as potential candidates for useful applications of quantum computing. Among quantum algorithms, the quantum approximate optimization algorithm (QAOA) is currently considered the most promising method to obtain a quantum advantage for such problems. The QAOA method uses a classical counterpart to perform optimization in a hybrid approach. In this paper, we show that the recently introduced method called quantum circuit evolutionary (QCE) also has potential for applications in binary optimization problems. This methodology is classical optimizer-free, but, for some scenarios, may have convergence stagnation as a consequence of smooth circuit modifications at each generation. To avoid this drawback and accelerate the convergence capabilities of QCE, we introduce a framework using an adaptive cost function (ACF), which varies dynamically with the circuit evolution. This procedure accelerates the convergence of the method. Applying this new approach to instances of the set partitioning problem, we show that QCE-ACF achieves convergence performance identical to QAOA but with a shorter execution time. Finally, experiments in the presence of induced noise show that this framework is quite suitable for the noisy intermediate-scale quantum era.