Efficient Inversion of Unknown Unitary Operations with Structured Hamiltonians

Fuente: arXiv
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Main Authors: Mo, Yin, Lin, Tengxiang, Wang, Xin
Format: Preprint
Published: 2025
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author Mo, Yin
Lin, Tengxiang
Wang, Xin
author_facet Mo, Yin
Lin, Tengxiang
Wang, Xin
contents Unknown unitary inversion is a fundamental primitive in quantum computing and physics. Although recent work has demonstrated that quantum algorithms can invert arbitrary unknown unitaries without accessing their classical descriptions, improving the efficiency of such protocols remains an open question. In this work, we present efficient quantum algorithms for inverting unitaries with specific Hamiltonian structures, achieving significant reductions in both ancilla qubit requirements and unitary query complexity. We identify cases where unitaries encoding exponentially many parameters can be inverted using only a single query. We further extend our framework to implement unitary complex conjugation and transposition operations, and develop modified protocols capable of inverting more general classes of Hamiltonians. We have also demonstrated the efficacy and robustness of our algorithms via numerical simulations under realistic noise conditions of superconducting quantum hardware. Our results establish more efficient protocols that improve the resources required for quantum unitary inversion when prior information about the quantum system is available, and provide practical methods for implementing these operations on near-term quantum devices.
format Preprint
id arxiv_https___arxiv_org_abs_2506_20570
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Efficient Inversion of Unknown Unitary Operations with Structured Hamiltonians
Mo, Yin
Lin, Tengxiang
Wang, Xin
Quantum Physics
Unknown unitary inversion is a fundamental primitive in quantum computing and physics. Although recent work has demonstrated that quantum algorithms can invert arbitrary unknown unitaries without accessing their classical descriptions, improving the efficiency of such protocols remains an open question. In this work, we present efficient quantum algorithms for inverting unitaries with specific Hamiltonian structures, achieving significant reductions in both ancilla qubit requirements and unitary query complexity. We identify cases where unitaries encoding exponentially many parameters can be inverted using only a single query. We further extend our framework to implement unitary complex conjugation and transposition operations, and develop modified protocols capable of inverting more general classes of Hamiltonians. We have also demonstrated the efficacy and robustness of our algorithms via numerical simulations under realistic noise conditions of superconducting quantum hardware. Our results establish more efficient protocols that improve the resources required for quantum unitary inversion when prior information about the quantum system is available, and provide practical methods for implementing these operations on near-term quantum devices.
title Efficient Inversion of Unknown Unitary Operations with Structured Hamiltonians
topic Quantum Physics
url https://arxiv.org/abs/2506.20570