Cited by 140Quantum Computing Algorithms and ArchitectureQuantum Information and CryptographyQuantum many-body systems

Quantum Principal Component Analysis Only Achieves an Exponential Speedup Because of Its State Preparation Assumptions

Open access
Tang, Ewin·2021·Physical Review Letters

Abstract

A central roadblock to analyzing quantum algorithms on quantum states is the lack of a comparable input model for classical algorithms. Inspired by recent work of the author [E. Tang, STOC 2019.], we introduce such a model, where we assume we can efficiently perform ℓ^{2}-norm samples of input data, a natural analog to quantum algorithms that assume efficient state preparation of classical data. Though this model produces less practical algorithms than the (stronger) standard model of classical computation, it captures versions of many of the features and nuances of quantum linear algebra algorithms. With this model, we describe classical analogs to Lloyd, Mohseni, and Rebentrost's quantum algorithms for principal component analysis [S. Lloyd, M. Mohseni, and P. Rebentrost, Nat. Phys. 10, 631 (2014).NPAHAX1745-247310.1038/nphys3029] and nearest-centroid clustering [S. Lloyd, M. Mohseni, and P. Rebentrost, Quantum algorithms for supervised and unsupervised machine learning]. Since they are only polynomially slower, these algorithms suggest that the exponential speedups of their quantum counterparts are simply an artifact of state preparation assumptions.

Integrity signals

Registry

Crossref · 10.1103/physrevlett.127.060503

Cites

8 of 8 references verified0 citation errors · 0 not checkable

Statistics

Recomputing p-values needs the paper’s full text.

Claims the paper makes

We couldn’t retrieve this paper’s full text, so its claims and self-check weren’t run. The registry and citation checks still apply.

Claims other papers make about this one

Each is checked against this paper’s own text: does it say what the citing paper says it does?

  • These quantum machine learning approaches need careful consideration of subtle issues that do not appear in classical algorithms and are strongly intertwined with the underlying hardware.

    “Regardless of the conditions of their advantages, these approaches need careful consideration of subtle issues (see, e.g., Refs.[112-115]) that do not appear in classical algorithms and are, in particular, strongly intertwined with the underlying hardware.”

Cites

Flagged first, then by citations

Cited by

Sorted by citations

Authors
Tang, E.
Affiliations
University of Washington (US)
Corresponding author
Tang, Ewin
Venue
Physical Review Letters
Published
2021-08-04
Volume
127
Issue
6
Pages
060503-060503
ISSN
  • 0031-9007 (ISSN-L)
  • 1079-7114
OpenAlex
W3192002582
Cited by
140
References
8
Citations by year
2026: 16 · 2025: 23 · 2024: 26 · 2023: 25 · 2022: 25 · 2021: 12 · 2020: 7 · 2019: 4 · 2018: 2
FWCI
7.78
Type
journal article
Language
en
Open access
Locations
  • Physical Review Letters (publishedVersion)
  • PubMed (publishedVersion)
  • arXiv (Cornell University) (submittedVersion)
  • arXiv (Cornell University)
Funders
National Science Foundation (DGE-1762114)
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
quantum principal component analysis, quantum linear algebra, quantum state preparation, exponential speedup, quantum machine learning

About these checks

Registry, retraction, Cites and statistics results are computed, not judged, with one exception: a printed reference that no index lists is read once by a model before it counts as a citation error. Claims are extracted by a model and kept only when their quote appears verbatim in the text; each cited source is then checked, with a model’s help, for whether it says what the claim relies on. Those verdicts can be wrong — read the claim’s quote and the cited source before relying on one.

Statistics and arithmetic are recomputed, not judged.

Confidence bands are shown only for fields calibrated on our annotated test set. None is calibrated yet, so no band is shown.

What counts as a claim ›How we measure confidence ›How we check this ›

Are you an author, or do you see a problem with this page? Request a review