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Historical timeline

Three foundational papers on Wick contractions and spectral representations, in historical context.

This short chronology follows three papers used in the core lessons; it is not a complete history or a claim of sole priority.

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3entries

  • Wick's collision-matrix paper

    Gian-Carlo Wick published the contraction method now called Wick's theorem in a 1950 Physical Review paper.

    Applies to: The 1950 publication introducing the normal-product contraction method for collision-matrix calculations.

    • The publication date records this paper, not an exhaustive priority determination for every precursor or equivalent formulation.
    Date
    1950
    Participants
    Gian-Carlo Wick
    Significance
    The paper supplies the primary historical source for the contraction identity used in perturbative expansions.
    Interpretation note
    Publication chronology alone does not settle all questions of priority or precursor influence.

    Historical treatment: Wick Expansion for Interacting Fields

    Sources: The Evaluation of the Collision MatrixGian-Carlo Wick

    Notation and checks
    Also called
    Wick theorem publication, The Evaluation of the Collision Matrix

  • Källén's spectral-representation paper

    Gunnar Källén published a 1952 paper on field and charge renormalization that is a primary source for the spectral representation.

    Applies to: Källén's 1952 analysis of field and charge renormalization and the spectral content of propagators.

    • The record does not infer sole priority from publication date and is paired with the later Lehmann source.
    Date
    1952
    Participants
    Gunnar Källén
    Significance
    The paper connects intermediate-state spectral information to the normalization and renormalization of fields.
    Interpretation note
    The eponym joins distinct Källén and Lehmann papers; this record avoids a sole-priority inference.

    Historical treatment: The Källén–Lehmann Representation

    Sources: On the Definition of the Renormalization Constants in Quantum Electrodynamics

    Notation and checks
    Also called
    Källén spectral representation, Källén–Lehmann history

  • Lehmann's propagation-functions paper

    Harry Lehmann published a 1954 paper on propagation functions and renormalization constants that completes the paired primary-source history of the spectral representation.

    Applies to: Lehmann's 1954 analysis of propagation functions and renormalization constants.

    • The record describes the consulted paper and makes no exhaustive priority claim.
    Date
    1954
    Participants
    Harry Lehmann
    Significance
    The paper develops the propagation-function representation from intermediate states and their spectral weights.
    Interpretation note
    The record is paired with Källén's 1952 paper and does not flatten their different contributions.

    Historical treatment: The Källén–Lehmann Representation

    Sources: On the Properties of Propagation Functions and Renormalization Constants of Quantized Fields

    Notation and checks
    Also called
    Lehmann spectral representation, Källén–Lehmann history