Large time-step discretisation of adiabatic quantum dynamics

Fuente: arXiv
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Main Authors: An, Dong, Costa, Pedro C. S., Berry, Dominic W.
Format: Preprint
Published: 2025
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author An, Dong
Costa, Pedro C. S.
Berry, Dominic W.
author_facet An, Dong
Costa, Pedro C. S.
Berry, Dominic W.
contents Adiabatic quantum computing is a general framework for preparing eigenstates of Hamiltonians on quantum devices. However, its digital implementation requires an efficient Hamiltonian simulation subroutine, which may introduce extra computational overhead or complicated quantum control logic. In this work, we show that the time step sizes in time discretization can be much larger than expected, and the overall complexity is greatly reduced. Remarkably, regardless of the general convergence order of the numerical method, we can choose a uniform time step size independent of tolerated error and evolution time for sufficiently accurate simulation. Furthermore, with the boundary cancellation condition where the continuous diabatic errors are exponentially suppressed, we provide strong evidence on an exponential convergence of even first-order Trotter with uniform time step size. We apply our analysis to the example of adiabatic unstructured search and show several preferable features of the Trotterized adiabatic approach: it can match the Grover lower bound, it does not require a priori knowledge on the number of marked states, and its performance can be asymptotically comparable with that of the quantum approximate optimization algorithm.
format Preprint
id arxiv_https___arxiv_org_abs_2509_00171
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Large time-step discretisation of adiabatic quantum dynamics
An, Dong
Costa, Pedro C. S.
Berry, Dominic W.
Quantum Physics
Numerical Analysis
Adiabatic quantum computing is a general framework for preparing eigenstates of Hamiltonians on quantum devices. However, its digital implementation requires an efficient Hamiltonian simulation subroutine, which may introduce extra computational overhead or complicated quantum control logic. In this work, we show that the time step sizes in time discretization can be much larger than expected, and the overall complexity is greatly reduced. Remarkably, regardless of the general convergence order of the numerical method, we can choose a uniform time step size independent of tolerated error and evolution time for sufficiently accurate simulation. Furthermore, with the boundary cancellation condition where the continuous diabatic errors are exponentially suppressed, we provide strong evidence on an exponential convergence of even first-order Trotter with uniform time step size. We apply our analysis to the example of adiabatic unstructured search and show several preferable features of the Trotterized adiabatic approach: it can match the Grover lower bound, it does not require a priori knowledge on the number of marked states, and its performance can be asymptotically comparable with that of the quantum approximate optimization algorithm.
title Large time-step discretisation of adiabatic quantum dynamics
topic Quantum Physics
Numerical Analysis
url https://arxiv.org/abs/2509.00171