Analytic and Stochastic Approach to Quantum Advantages in Ground State and Quantum State Preparation Problems

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Hauptverfasser: Ko, Taehee, Lim, Sungbin
Format: Preprint
Veröffentlicht: 2025
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author Ko, Taehee
Lim, Sungbin
author_facet Ko, Taehee
Lim, Sungbin
contents We study the problems of state preparation, ground state preparation and quantum state preparation. We propose an analytic approach to a stochastic quantum algorithm which prepares the ground state for $n$-qubit Hamiltonian that is represented by $\text{poly}(n)$ Pauli operators and has an inverse-polynomial gap, requiring only $\text{poly}(n)$ Pauli rotations, measurements, and classical time complexity when $n$ exceeds a threshold, to inverse-polynomial precision given the initial overlap being lower bounded by $\frac{1}{2^n}$. Extending this result, we prove that any $n$-qubit quantum state can be prepared in two regimes: (1) with a constant number of Pauli rotations to constant precision, or (2) with a polynomial number of rotations to inverse-polynomial precision. Our results improve over previous approaches to quantum state preparation in terms of gate complexity, thereby yielding quantum space advantage. As an application, we identify a practical condition under which quadratic unconstrained binary optimization (QUBO) problems can be solved with exponential quantum speedups.
format Preprint
id arxiv_https___arxiv_org_abs_2510_01563
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Analytic and Stochastic Approach to Quantum Advantages in Ground State and Quantum State Preparation Problems
Ko, Taehee
Lim, Sungbin
Quantum Physics
Numerical Analysis
Probability
We study the problems of state preparation, ground state preparation and quantum state preparation. We propose an analytic approach to a stochastic quantum algorithm which prepares the ground state for $n$-qubit Hamiltonian that is represented by $\text{poly}(n)$ Pauli operators and has an inverse-polynomial gap, requiring only $\text{poly}(n)$ Pauli rotations, measurements, and classical time complexity when $n$ exceeds a threshold, to inverse-polynomial precision given the initial overlap being lower bounded by $\frac{1}{2^n}$. Extending this result, we prove that any $n$-qubit quantum state can be prepared in two regimes: (1) with a constant number of Pauli rotations to constant precision, or (2) with a polynomial number of rotations to inverse-polynomial precision. Our results improve over previous approaches to quantum state preparation in terms of gate complexity, thereby yielding quantum space advantage. As an application, we identify a practical condition under which quadratic unconstrained binary optimization (QUBO) problems can be solved with exponential quantum speedups.
title Analytic and Stochastic Approach to Quantum Advantages in Ground State and Quantum State Preparation Problems
topic Quantum Physics
Numerical Analysis
Probability
url https://arxiv.org/abs/2510.01563