Tridiagonal matrix decomposition for Hamiltonian simulation on a quantum computer

Fuente: arXiv
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Main Authors: Arseniev, Boris, Guskov, Dmitry, Sengupta, Richik, Biamonte, Jacob, Zacharov, Igor
Format: Preprint
Published: 2023
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author Arseniev, Boris
Guskov, Dmitry
Sengupta, Richik
Biamonte, Jacob
Zacharov, Igor
author_facet Arseniev, Boris
Guskov, Dmitry
Sengupta, Richik
Biamonte, Jacob
Zacharov, Igor
contents The construction of quantum circuits to simulate Hamiltonian evolution is central to many quantum algorithms. State-of-the-art circuits are based on oracles whose implementation is often omitted, and the complexity of the algorithm is estimated by counting oracle queries. However, in practical applications, an oracle implementation contributes a large constant factor to the overall complexity of the algorithm. The key finding of this work is the efficient procedure for representation of a tridiagonal matrix in the Pauli basis, which allows one to construct a Hamiltonian evolution circuit without the use of oracles. The procedure represents a general tridiagonal matrix $2^n \times 2^n$ by systematically determining all Pauli strings present in the decomposition, dividing them into commuting subsets. The efficiency is in the number of commuting subsets $O(n)$. The method is demonstrated using the one-dimensional wave equation, verifying numerically that the gate complexity as function of the number of qubits is lower than the oracle based approach for $n < 15$ and requires half the number of qubits. This method is applicable to other Hamiltonians based on the tridiagonal matrices.
format Preprint
id arxiv_https___arxiv_org_abs_2310_00121
institution arXiv
publishDate 2023
record_format arxiv
spellingShingle Tridiagonal matrix decomposition for Hamiltonian simulation on a quantum computer
Arseniev, Boris
Guskov, Dmitry
Sengupta, Richik
Biamonte, Jacob
Zacharov, Igor
Quantum Physics
Emerging Technologies
The construction of quantum circuits to simulate Hamiltonian evolution is central to many quantum algorithms. State-of-the-art circuits are based on oracles whose implementation is often omitted, and the complexity of the algorithm is estimated by counting oracle queries. However, in practical applications, an oracle implementation contributes a large constant factor to the overall complexity of the algorithm. The key finding of this work is the efficient procedure for representation of a tridiagonal matrix in the Pauli basis, which allows one to construct a Hamiltonian evolution circuit without the use of oracles. The procedure represents a general tridiagonal matrix $2^n \times 2^n$ by systematically determining all Pauli strings present in the decomposition, dividing them into commuting subsets. The efficiency is in the number of commuting subsets $O(n)$. The method is demonstrated using the one-dimensional wave equation, verifying numerically that the gate complexity as function of the number of qubits is lower than the oracle based approach for $n < 15$ and requires half the number of qubits. This method is applicable to other Hamiltonians based on the tridiagonal matrices.
title Tridiagonal matrix decomposition for Hamiltonian simulation on a quantum computer
topic Quantum Physics
Emerging Technologies
url https://arxiv.org/abs/2310.00121