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Solving Quadratic Equations via PhaseLift when There Are About As Many Equations As Unknowns

Information Theory 2012-09-18 v2 math.IT Numerical Analysis

Abstract

This note shows that we can recover a complex vector x in C^n exactly from on the order of n quadratic equations of the form |<a_i, x>|^2 = b_i, i = 1, ..., m, by using a semidefinite program known as PhaseLift. This improves upon earlier bounds in [3], which required the number of equations to be at least on the order of n log n. We also demonstrate optimal recovery results from noisy quadratic measurements; these results are much sharper than previously known results.

Keywords

Cite

@article{arxiv.1208.6247,
  title  = {Solving Quadratic Equations via PhaseLift when There Are About As Many Equations As Unknowns},
  author = {Emmanuel J. Candes and Xiaodong Li},
  journal= {arXiv preprint arXiv:1208.6247},
  year   = {2012}
}

Comments

6 pages

R2 v1 2026-06-21T21:57:29.701Z