# A Theory of Quantum Subspace Diagonalization

@article{Epperly2021ATO, title={A Theory of Quantum Subspace Diagonalization}, author={E.N. Epperly and Lin Lin and Yuji Nakatsukasa}, journal={ArXiv}, year={2021}, volume={abs/2110.07492} }

Quantum subspace diagonalization methods are an exciting new class of algorithms for solving large scale eigenvalue problems using quantum computers. Unfortunately, these methods require the solution of an ill-conditioned generalized eigenvalue problem, with a matrix pencil corrupted by a non-negligible amount of noise that is far above the machine precision. Despite pessimistic predictions from classical perturbation theories, these methods can perform reliably well if the generalized…

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