Experimental demonstration of Robust Amplitude Estimation on near-term quantum devices for chemistry applications

This study explores hardware implementation of Robust Amplitude Estimation (RAE) on IBM quantum devices, demonstrating its application in quantum chemistry for one- and two-qubit Hamiltonian systems. Known for potentially offering quadratic speedups over traditional methods in estimating expectation values, RAE is evaluated under realistic noisy conditions. Our experiments provide detailed insights into the practical challenges associated with RAE. We achieved a significant reduction in sampling requirements compared to direct measurement techniques. In estimating the ground state energy of the hydrogen molecule, the RAE implementation demonstrated two orders of magnitude better accuracy for the two-qubit experiments and achieved chemical accuracy. These findings reveal its potential to enhance computational efficiencies in quantum chemistry applications despite the inherent limitations posed by hardware noise. We also found that its performance can be adversely impacted by coherent error and device stability and does not always correlate with the average gate error. These results underscore the importance of adapting quantum computational methods to hardware specifics to realize their full potential in practical scenarios.