Accelerating Feedback-Based Quantum Algorithms through Time Rescaling

Abstract

This work investigates the impact of time rescaling on the performance of Feedback Quantum Algorithms (FQA) and their variant for optimization tasks, FALQON. We introduce TR-FQA and TR-FALQON, time-rescaled versions of FQA and FALQON, respectively. The method is applied to two representative problems: the MaxCut combinatorial optimization problem and ground-state preparation in the ANNNI quantum many-body model. The results show that TR-FALQON accelerates convergence to the optimal solution in the early layers of the circuit, significantly outperforming its standard counterpart in shallow-depth regimes. In the context of state preparation, TR-FQA demonstrates superior convergence, reducing the required circuit depth by several hundred layers. These findings highlight the potential of time rescaling as a strategy to enhance algorithmic performance on near-term quantum devices.