Corpus ID: 237503498

Quantum Krylov subspace algorithms for ground and excited state energy estimation

  title={Quantum Krylov subspace algorithms for ground and excited state energy estimation},
  author={Cristian L. Cortes and Stephen K. Gray},
  • C. Cortes, Stephen K. Gray
  • Published 14 September 2021
  • Physics
Quantum Krylov subspace diagonalization (QKSD) algorithms provide a low-cost alternative to the conventional quantum phase estimation algorithm for estimating the ground and excited-state energies of a quantum many-body system. While QKSD algorithms typically rely on using the Hadamard test for estimating Krylov subspace matrix elements of the form, 〈φi|e |φj〉, the associated quantum circuits require an ancilla qubit with controlled multi-qubit gates that can be quite costly for near-term… Expand

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