Cited by 2,368Quantum Computing Algorithms and ArchitectureQuantum Information and CryptographyQuantum many-body systems

Efficient Classical Simulation of Slightly Entangled Quantum Computations

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Vidal, Guifré·2003·Physical Review Letters

Abstract

We present a classical protocol to efficiently simulate any pure-state quantum computation that involves only a restricted amount of entanglement. More generally, we show how to classically simulate pure-state quantum computations on n qubits by using computational resources that grow linearly in n and exponentially in the amount of entanglement in the quantum computer. Our results imply that a necessary condition for an exponential computational speedup (with respect to classical computations) is that the amount of entanglement increases with the size n of the computation, and provide an explicit lower bound on the required growth.

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Registry

Crossref · 10.1103/physrevlett.91.147902

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14 of 14 references verified0 citation errors · 0 not checkable

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  • Statistics converge smoothly to an asymptote, consistent with an exponential tail of truncated singular values.

    “Statistics converge smoothly to an asymptote as shown, consistent with an exponential tail of truncated singular values 59 .”

    From Beyond-classical computation in quantum simulation (2025) · cites this paper as [59]

    The discussion of truncated Schmidt decompositions (p. 4) explains that discarding small Schmidt coefficients can yield an accurate approximation. It does not describe an exponential tail of those coefficients. The sentence presents the smooth convergence of statistics as the citing authors’ observation, rather than a result attributed to Vidal. (LLM, conf=0.82)

    Experimental — accuracy not yet measured
  • The parameterized quantum circuit features a one-dimensional connectivity pattern, making it suitable for representation using a Matrix Product State (MPS).

    “The parameterized quantum circuit in our study features a one-dimensional connectivity pattern, making it suitable for representation using a Matrix Product State (MPS) [56], [57], [58].”
  • In this work, the multiplicative inverse of α is calculated with seven multipliers, verified by quantum circuit simulation by matrix product state.

    “Slight modification of previous method is found in this work with seven multipliers being used, verified by the quantum circuit simulation by matrix product state [52].”
  • χ_Q shows exponential dependence on L, consistent with area-law scaling.

    “Crucially, we observe exponential dependence on L, which is consistent with area-law scaling 59 .”

    From Beyond-classical computation in quantum simulation (2025) · cites this paper as [59]

    The paper defines Schmidt rank χ as an entanglement measure (p. 1) and discusses exponential dependence of simulation resources on entanglement (p. 3). It does not address χ_Q, exponential scaling with L, or whether that scaling is consistent with an area law; searches for area-law and boundary-size scaling found no such passage. (LLM, conf=0.72)

    Experimental — accuracy not yet measured
  • Series methods (Taylor, Padé, Chebyshev) are accurate for small matrices but prohibitively expensive for larger systems.

    “The Taylor expansion, Pad´ e approximant, and Chebyshev approximant are series methods based on powers of the Hamiltonian 150,151 to approximate the evolution operator. They are accurate for small matrices but prohibitively expensive for larger systems.”

    From Quantum Chemistry in the Age of Quantum Computing (2019) · cites this paper as [151]

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Authors
Vidal, G.
Affiliations
California Institute of Technology (US)
Corresponding author
Vidal, Guifré
Venue
Physical Review Letters
Published
2003-10-01
Volume
91
Issue
14
Pages
147902-147902
ISSN
  • 0031-9007 (ISSN-L)
  • 1079-7114
OpenAlex
W2036604884
Cited by
2,368
References
14
Citations by year
2026: 113 · 2025: 201 · 2024: 152 · 2023: 133 · 2022: 151 · 2021: 170 · 2020: 148 · 2019: 133 · 2018: 100 · 2017: 120 · 2016: 94 · 2015: 114 · 2014: 109 · 2013: 92 · 2012: 81
FWCI
36.79
Type
journal article
Language
en
Open access
Locations
  • Physical Review Letters (publishedVersion)
  • PubMed (publishedVersion)
  • arXiv (Cornell University) (submittedVersion)
  • arXiv (Cornell University)
Topics
  • Physical Sciences › Computer Science › Artificial Intelligence › Quantum Computing Algorithms and Architecture
  • Physical Sciences › Computer Science › Artificial Intelligence › Quantum Information and Cryptography
  • Physical Sciences › Physics and Astronomy › Atomic and Molecular Physics, and Optics › Quantum many-body systems
Keywords
classical simulation of quantum computation, entanglement, linear optical quantum computation, exponential speedup, entanglement growth, lower bounds

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