Quantum Krylov Subspace Diagonalization via Time Reversal Symmetries

Fuente: arXiv
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Main Authors: Mariella, Nicola, Rico, Enrique, Byrne, Adam, Zhuk, Sergiy
Format: Preprint
Published: 2025
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author Mariella, Nicola
Rico, Enrique
Byrne, Adam
Zhuk, Sergiy
author_facet Mariella, Nicola
Rico, Enrique
Byrne, Adam
Zhuk, Sergiy
contents Krylov quantum diagonalization methods have emerged as a promising use case for quantum computers. However, many existing implementations rely on controlled operations, which pose challenges to near-term quantum hardware. We introduce a novel protocol, termed Krylov Time Reversal (KTR), that circumvents these bottlenecks by leveraging time-reversal symmetry in Hamiltonian evolution. Using symmetric time dynamics, we show that it is possible to recover real-valued Krylov matrix elements, which significantly reduces the circuit depth and enhances compatibility with shallow quantum architectures. Furthermore, the protocol's structure indirectly reduces the total evolution time, benefiting both near-term and long-term architectures. We validate our method through numerical simulations on paradigmatic Hamiltonians exhibiting time-reversal symmetry, including the transverse-field Ising model and a lattice gauge theory, demonstrating accurate spectral estimation and favorable circuit constructions.
format Preprint
id arxiv_https___arxiv_org_abs_2507_22559
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Quantum Krylov Subspace Diagonalization via Time Reversal Symmetries
Mariella, Nicola
Rico, Enrique
Byrne, Adam
Zhuk, Sergiy
Quantum Physics
Krylov quantum diagonalization methods have emerged as a promising use case for quantum computers. However, many existing implementations rely on controlled operations, which pose challenges to near-term quantum hardware. We introduce a novel protocol, termed Krylov Time Reversal (KTR), that circumvents these bottlenecks by leveraging time-reversal symmetry in Hamiltonian evolution. Using symmetric time dynamics, we show that it is possible to recover real-valued Krylov matrix elements, which significantly reduces the circuit depth and enhances compatibility with shallow quantum architectures. Furthermore, the protocol's structure indirectly reduces the total evolution time, benefiting both near-term and long-term architectures. We validate our method through numerical simulations on paradigmatic Hamiltonians exhibiting time-reversal symmetry, including the transverse-field Ising model and a lattice gauge theory, demonstrating accurate spectral estimation and favorable circuit constructions.
title Quantum Krylov Subspace Diagonalization via Time Reversal Symmetries
topic Quantum Physics
url https://arxiv.org/abs/2507.22559