🤖 AI Summary
For integer-constrained combinatorial optimization problems—such as discrete mean-variance portfolio optimization—existing quantum annealing approaches fail to exploit the smooth, convex structure of their continuous relaxations. This work proposes a continuous-relaxation-guided quantum warm-start method: it explicitly incorporates the continuous optimal solution into the QUBO formulation, thereby tightly constraining the search space to a neighborhood of nearby integer solutions. This strategy drastically reduces the Hilbert space dimensionality and the required number of qubits. To our knowledge, this is the first systematic integration of continuous relaxation information into QUBO construction for quantum annealing. Experiments on the D-Wave Advantage system demonstrate that the proposed method significantly outperforms state-of-the-art classical and quantum optimizers in both solution quality and computational efficiency.
📝 Abstract
Combinatorial optimization with a smooth and convex objective function arises naturally in applications such as discrete mean-variance portfolio optimization, where assets must be traded in integer quantities. Although optimal solutions to the associated smooth problem can be computed efficiently, existing adiabatic quantum optimization methods cannot leverage this information. Moreover, while various warm-starting strategies have been proposed for gate-based quantum optimization, none of them explicitly integrate insights from the relaxed continuous solution into the QUBO formulation. In this work, a novel approach is introduced that restricts the search space to discrete solutions in the vicinity of the continuous optimum by constructing a compact Hilbert space, thereby reducing the number of required qubits. Experiments on software solvers and a D-Wave Advantage quantum annealer demonstrate that our method outperforms state-of-the-art techniques.