- Assessing the stability of noisy quantum computations(arXiv)
Writer : Samudra Dasgupta, Travis S. Humble
abstract: Quantum computation has made significant progress over the past decade, with several new technologies providing proof-of-principle experimental demonstrations of these computations. However, these experimental demonstrations of quantum computation face technical challenges due to noise and errors introduced by imperfect implementations of the technique. Here we construct the concepts of computational accuracy, result reproducibility, device reliability and program stability in the context of quantum computation. We provide intuitive definitions of these concepts in the context of quantum computation leading from program outputs to operationally meaningful ranges. Our assessment highlights the ongoing need for statistical analysis of quantum computing programs to increase our confidence in the burgeoning field of quantum information science.
2. Calculating the ground state energy of benzene under spatial transformation with noisy quantum computing(arXiv)
Writer : Wasile Senane, Jean-Philippe Piquemal, Marco J. Rancici
abstract: In this manuscript, we use a variational quantum eigensolver (VQE) to calculate the ground state energy of benzene under spatial transformation. The main goal of this work is to estimate the feasibility of using quantum computing ansatze in short-lived devices to solve problems with large numbers of orbitals in regions where classical methods are known to fail. We also combined an advanced simulation platform with a real quantum computer to analyze how noise inherent in quantum computers affects the results. Central to our research is the hardware-efficient, quantum single-coupled cluster ansatze (qUCC). First, we find that the hardware-efficient ansatz outperforms the mean-field method for extreme strains in benzene. However, a major problem is maintaining equilibrium, which hinders practical chemical applications. Additionally, hardware-efficient ansatz produces results that depend heavily on initial guesses of parameters both with and without noise, and the optimization problem has a greater impact on convergence than noise. This is confirmed by comparison with actual quantum computing experiments. On the other hand, the qUCC ansatz alternative represents a deeper circuit. Therefore, the noise effect increases and is so extreme that the method does not outperform the mean field theory. The qUCC’s dual simulator/8–16 qubit QPU calculations appear to be much more sensitive to hardware noise than shot noise, which provides further indications of where noise reduction efforts should be headed. Finally, this study shows that the qUCC method better captures the physics of the system because it can be exploited with the Huckel approximation. We discussed how going beyond this approximation dramatically increases the optimization complexity of such difficult problems. △ less
three.Efficiently improving the performance of noisy quantum computers (arXiv)
Writer : Samuele Ferracin, Akel Hashim, Jean-Loup Ville, Ravi Naik, Arnaud Carignan-Dugas, Hammam Qassim, Alexis Morvan, David I. Santiago, Irfan Siddiqi, Joel J. Wallman
abstract: Using short-term quantum computers to achieve quantum advantages requires efficient strategies to improve the performance of currently available noisy quantum devices. We develop and experimentally verify two efficient error mitigation protocols, “noise-free output extrapolation” and “Powley error rejection”, which can significantly improve the performance of quantum circuits composed of noise cycles of gates. By combining popular mitigation strategies such as stochastic error rejection and noise amplification with efficient noise reconstruction methods, our protocol mitigates a wide range of noise processes that do not meet the basic assumptions of existing mitigation protocols, including nonlocal and gate-dependent processes. You can. Test the protocol on a 4-qubit superconducting processor on the Advanced Quantum Testbed. Performance of both structured and random circuits is significantly improved, with up to 86% improvement in variation distance compared to unrelaxed output. Our experiments demonstrate the efficiency of the protocol and its practicality for current hardware platforms.