Simultaneously optimizing symmetry shifts and tensor factorizations for cost-efficient Fault-Tolerant Quantum Simulations of electronic Hamiltonians

Fuente: arXiv
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Auteurs principaux: Deka, Konrad, Zak, Emil
Format: Preprint
Publié: 2024
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author Deka, Konrad
Zak, Emil
author_facet Deka, Konrad
Zak, Emil
contents In fault-tolerant quantum computing, the cost of calculating Hamiltonian eigenvalues using the quantum phase estimation algorithm is proportional to the constant scaling the Hamiltonian matrix block-encoded in a unitary circuit. We present a method to reduce this scaling constant for the electronic Hamiltonians represented as a linear combination of unitaries. Our approach combines the double tensor-factorization method of Burg et al. with the the block-invariant symmetry shift method of Loaiza and Izmaylov. By extending the electronic Hamiltonian with appropriately parametrized symmetry operators and optimizing the tensor-factorization parameters, our method achieves a 25% reduction in the block-encoding scaling constant compared to previous techniques. The resulting savings in the number of non-Clifford T-gates, which are an essential resource for fault-tolerant quantum computation, are expected to accelerate the feasiblity of practical Hamiltonian simulations. We demonstrate the effectiveness of our technique on Hamiltonians of industrial and biological relevance, including the nitrogenase cofactor (FeMoCo) and cytochrome P450.
format Preprint
id arxiv_https___arxiv_org_abs_2412_01338
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Simultaneously optimizing symmetry shifts and tensor factorizations for cost-efficient Fault-Tolerant Quantum Simulations of electronic Hamiltonians
Deka, Konrad
Zak, Emil
Quantum Physics
Chemical Physics
68Q12, 68Q17, 81P68, 81-08, 81-10, 81V74, 81V55
G.1.2; G.1.3; G.1.6; I.6.1
In fault-tolerant quantum computing, the cost of calculating Hamiltonian eigenvalues using the quantum phase estimation algorithm is proportional to the constant scaling the Hamiltonian matrix block-encoded in a unitary circuit. We present a method to reduce this scaling constant for the electronic Hamiltonians represented as a linear combination of unitaries. Our approach combines the double tensor-factorization method of Burg et al. with the the block-invariant symmetry shift method of Loaiza and Izmaylov. By extending the electronic Hamiltonian with appropriately parametrized symmetry operators and optimizing the tensor-factorization parameters, our method achieves a 25% reduction in the block-encoding scaling constant compared to previous techniques. The resulting savings in the number of non-Clifford T-gates, which are an essential resource for fault-tolerant quantum computation, are expected to accelerate the feasiblity of practical Hamiltonian simulations. We demonstrate the effectiveness of our technique on Hamiltonians of industrial and biological relevance, including the nitrogenase cofactor (FeMoCo) and cytochrome P450.
title Simultaneously optimizing symmetry shifts and tensor factorizations for cost-efficient Fault-Tolerant Quantum Simulations of electronic Hamiltonians
topic Quantum Physics
Chemical Physics
68Q12, 68Q17, 81P68, 81-08, 81-10, 81V74, 81V55
G.1.2; G.1.3; G.1.6; I.6.1
url https://arxiv.org/abs/2412.01338