Error mitigated quantum computational chemistry

Variational algorithms may solve important chemistry problems on near-future quantum computers. However, their potential is limited by hardware errors. It is therefore crucial to develop ways to mitigate these errors, with minimal additional resources. Here, we propose a stabiliser-based modification to the variational quantum eigensolver which enables the detection of up to 66% of depolarising errors. We use a single additional qubit to check conserved molecular quantities. Numerical simulations show that our method is able to significantly increase the accuracy of noisy chemistry calculations, especially when combined with other error mitigation techniques.

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