Classical combinations of quantum states for solving banded circulant linear systems

Fuente: arXiv
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Main Authors: Huang, Po-Wei, Li, Xiufan, Koor, Kelvin, Rebentrost, Patrick
Format: Preprint
Published: 2023
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author Huang, Po-Wei
Li, Xiufan
Koor, Kelvin
Rebentrost, Patrick
author_facet Huang, Po-Wei
Li, Xiufan
Koor, Kelvin
Rebentrost, Patrick
contents Solving linear systems is of great importance in numerous fields. Proposed quantum algorithms for preparing solutions for linear systems include the HHL algorithm with subsequent refinements and variational methods. Circulant linear systems appear in many physics-related differential equations. An interesting case is banded circulant linear systems whose non-zero terms are within distance K of the main diagonal. For these systems, we propose an approach based on the classical combination of quantum states (CQS) method relying on convex optimization against the available analytical solution. From decompositions into cyclic permutations, the solution can be approximately represented by a classical combination of a polynomial number of quantum states. We validate our methods using classical simulations as well as execution on an IBM quantum computer. While in the setting of this paper, efficient classical algorithms are available, our results demonstrate the potential applicability of the CQS method for solving physics problems such as heat transfer.
format Preprint
id arxiv_https___arxiv_org_abs_2309_11451
institution arXiv
publishDate 2023
record_format arxiv
spellingShingle Classical combinations of quantum states for solving banded circulant linear systems
Huang, Po-Wei
Li, Xiufan
Koor, Kelvin
Rebentrost, Patrick
Quantum Physics
Numerical Analysis
Solving linear systems is of great importance in numerous fields. Proposed quantum algorithms for preparing solutions for linear systems include the HHL algorithm with subsequent refinements and variational methods. Circulant linear systems appear in many physics-related differential equations. An interesting case is banded circulant linear systems whose non-zero terms are within distance K of the main diagonal. For these systems, we propose an approach based on the classical combination of quantum states (CQS) method relying on convex optimization against the available analytical solution. From decompositions into cyclic permutations, the solution can be approximately represented by a classical combination of a polynomial number of quantum states. We validate our methods using classical simulations as well as execution on an IBM quantum computer. While in the setting of this paper, efficient classical algorithms are available, our results demonstrate the potential applicability of the CQS method for solving physics problems such as heat transfer.
title Classical combinations of quantum states for solving banded circulant linear systems
topic Quantum Physics
Numerical Analysis
url https://arxiv.org/abs/2309.11451