Cited by 2,678Advanced Operator Algebra ResearchQuantum Information and CryptographyMatrix Theory and Algorithms

Completely positive linear maps on complex matrices

Open access
Choi, Man-Duen·1975·Linear Algebra and its Applications

Integrity signals

Registry

Crossref · 10.1016/0024-3795(75)90075-0

Cites

12 of 12 references verified0 citation errors · 0 not checkable

Statistics

Nothing to recompute.

Claims the paper makes

0 of 4 cited sources checked · 0 supported · 0 flagged

  • Findingreasoning

    If {u_i*} is linearly independent, then {V_i} is linearly independent.

    “For some improvement, we may require {u:} to be linearly independent, then {Vi} must be linearly independent too.”
    Quote in the paperSubstantial claim
  • Findingcitation

    A linear map Φ: M_m → M_n is hermitian-preserving iff it admits an expression Φ(A)=Σ ε_i V_i* A V_i where ε_i=±1 and V_i are n×m matrices.

    “Q : !JXn,+9Xm is hermitian-preserving iff @ admits an expression @(A) = Zei V;CAV, where ei = + 1, Vi are n X m matrices.”
    Quote in the paperSubstantial claim0 of 2 sources checked
    • cites [7, p. 134, Theorem 2.11]

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

    • cites [5, p. 259, Theorem 21]

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  • Findingreasoning

    A linear map Φ: M_m → M_n is hermitian-preserving iff (Φ(E_ik))_{jk} is hermitian.

    “For a linear map a: 9JIm,-+Izll,, it is obvious that Q is hermitian-preserving iff (@(Eik))jk is hermitian.”
    Quote in the paperNot a substantial claim
  • Findingreasoning

    A linear map Φ: M_m → M_n is completely positive iff the block matrix (Φ(E_jk))_{1≤j,k≤n} is positive.

    “THEOREM 2. Let Cp be a linear map from %!, to %Q,,,.Then @ is completely positive iff (@(Ejk))lG i,k9n is positiue.”
    Quote in the paperSubstantial claim
  • Findingreasoning

    Let {W_p} be n×m matrices. Φ has the expression Φ(A)=Σ W_p* A W_p iff there exists an isometric Γ'×Γ matrix (β_{pi}) such that W_p=Σ_i β_{pi} V_i for all p.

    “Let { W,}; be a class of n X m matrices, then Q, has the expression @(A) = X;W:AWp iff there exists an isometric I! ' x E matrix (@Pi, such that Wp = Zipppi Vi for all p.”
    Quote in the paperSubstantial claim
  • May combine two claims. 6
  • Classified as probably not a substantial claim. 1
  • May combine two claims.

    Findingreasoning

    The class of hermitian-preserving maps is a partially ordered vector space over the reals, and the class of completely positive linear maps is its positive cone.

    “Endowed with the natural ordering induced by !TQ,(!lP,J, the class of hermitian-preserving maps is a partially ordered vector space over the reals, while the class of completely positive linear maps is just the positive cone.”
    Quote in the paperSubstantial claim
  • May combine two claims.

    Findingreasoning

    If Φ: M_m → M_n is completely positive, it can be written as Φ(A)=Σ V_i* A V_i where {V_i} is a linearly independent class of n×m matrices; hence l ≤ nm.

    “Suppose a: YJ?”+%P, is completely positive.From Remark 4, we can write 0 in the form O(A) = Z,!VTAVi where { Vi} f is a class of linearly independent n X m matrices; hence e < nm.”
    Quote in the paperSubstantial claim
  • May combine two claims.

    Findingreasoning

    Moreover, if {W_p} is also a linearly independent set, then Γ'=Γ and (β_{pi}) is unitary.

    “Moreover, if { W,}; is also a linearly independent set, then F ' = I', and ( ppJpi is unitary.”
    Quote in the paperSubstantial claim
  • May combine two claims.

    Findingreasoning

    In the proof of Theorem 1, the expression (Φ(E_jk))^+ = Σ u_i* u_i is not unique, hence {V_i} is not uniquely determined.

    “In the proof of Theorem 1, the expression (@(Ejk))+ = Xi”* q is not unique, hence ( Vi} is not uniquely determined.”
    Quote in the paperSubstantial claim
  • May combine two claims.

    Premisereasoning

    CP[M_m,M_n;K] is convex and is the convex hull of its extreme points.

    “It is evident that CP[!&, iDi!,; K] is a convex set, hence it is the convex hull of its extreme points.”
    Quote in the paperSubstantial claim
  • May combine two claims.

    Premisenone given

    Each linear map Φ: M_m → M_n is determined by its values on E_ik; hence Φ is determined by the single element (Φ(E_jk))_{j,k}.

    “Each linear map Q, : !IR2,-+'171, is determined by its values on Eik.Hence ip is completely determined by the single element (@(Ejk))l < i, k G n E 9JIm, (TRJ.”
    Quote in the paperSubstantial claim
  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Interpretationreasoning

    In particular, if m=1, Φ is a pure state (an extreme identity-preserving positive functional) on M_n iff Φ is a vector state (there exists a unit vector u such that Φ(A)=u* A u for all A).

    “In particular, if m = I, we obtain the well-known fact that @ is a 'pure state' (an extreme identity-preserving positive functional) on YJ$, iff @ is a 'vector state' (i.e., there exists a unit vector u such that Q(A) = v*Av for all A).”
    Quote in the paperNot a substantial claim
7 of 7
  • The paper relies on this without support.

    Every positive matrix can be expressed as a sum of rank-one positive matrices (vectors).

    “As (E&< i,kGn is positive, so P(EjJ)r< j,k(n E !I&, (!l.R,J is positive; thus there exist vectors vi” (regarded as nm x 1 matrices) such that (Q(Ejk))jk =Z,uFvi.”
  • The paper relies on this without support.

    Theorem 7 is not valid for higher order matrices.

    “We remark that Theorem 7 is not valid for higher order matrices.This is just because the quoted result for an mm,-coefficient quadratic form cannot be generalized to the case of more than 2 real indeterminates, as will be shown in a forthcoming paper.”
2 of 2

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?

  • The trace norm of the Choi-Jamiołkowski matrix of E(t,t1) equals 1 if E(t,t1) is completely positive and is greater than 1 otherwise.

    “E (t,t 1 ) ⊗ 1 1 (| |) 1 = 1 iff E (t,t 1 ) is CP, > 1 otherwise.”

    From Quantum non-Markovianity: characterization, quantification and detection (2014) · cites this paper as [19]

    Theorem 2 (in the copy’s Abstract section; page not provided) states that a map is completely positive if and only if its associated matrix is positive. The copy does not state the claimed trace-norm criterion or establish the normalization needed for a threshold of 1. (LLM, conf=0.86)

    Experimental — accuracy not yet measured
  • Completely positive maps are easier to characterize than merely positive maps and have a Kraus representation.

    “Complete positive maps are much easier to characterize than maps that are merely positive [19,20]; they admit the so-called Kraus representation,”
  • For a Hilbert space with finite dimension N_S = dim H_S, complete positivity is equivalent to N_S-positivity.

    “for a Hilbert space with finite dimension N S = dim H S complete positivity is equivalent to N S -positivity [13].”

    From Foundations and measures of quantum non-Markovianity (2012) · cites this paper as [13]

  • Choi's theorem states that a linear map on Mn is completely positive exactly when its amplification by the identity on Mn is positivity-preserving, equivalently when the block matrix (20) is positive semidefinite.

    “Theorem 5. A linear map : M n → M n is completely positive if and only if ⊗ I M n is positivity-preserving on M n ⊗ M n or equivalently, if and only if the matrix”
  • The minimal number of Kraus operators needed to represent a completely positive map in form (1) equals rank[β( )].

    “Lemma 10.The minimal number of Kraus operators A k needed to represent a completely positive map in the form (1) is rank[β( )].”

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Authors
Choi, M.-D.
Affiliations
University of California, Berkeley (US)
Corresponding author
Choi, Man-Duen
Venue
Linear Algebra and its Applications
Publisher
Elsevier BV
Published
1975-06
Volume
10
Issue
3
Pages
285-290
ISSN
0024-3795 (ISSN-L)
OpenAlex
W2116102644
Cited by
2,659
References
12
Citations by year
2026: 122 · 2025: 216 · 2024: 189 · 2023: 205 · 2022: 161 · 2021: 167 · 2020: 132 · 2019: 152 · 2018: 112 · 2017: 98 · 2016: 95 · 2015: 100 · 2014: 93 · 2013: 90 · 2012: 97
FWCI
4.55
Type
journal article
Language
en
Open access
Locations
Linear Algebra and its Applications (publishedVersion)
Topics
  • Physical Sciences › Mathematics › Mathematical Physics › Advanced Operator Algebra Research
  • Physical Sciences › Computer Science › Artificial Intelligence › Quantum Information and Cryptography
  • Physical Sciences › Computer Science › Computational Theory and Mathematics › Matrix Theory and Algorithms
Keywords
complex matrices, matrix algebra, positive linear maps, operator algebras

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