PRL Supplemental Material (prl-supplementary)

When to trigger

• The Letter is over length and detail must move out of the body
• A reader cannot follow the Letter without consulting the SM
• You have derivations, extended datasets, or methods detail with no home
• You are unsure what is allowed in SM versus what must stay in the Letter
• Referees of a prior version asked for material that would bloat the body

The stand-alone rule (non-negotiable)

The Letter must be fully understandable on its own. The Supplemental Material supports the Letter; it must never be load-bearing for the central claim. A reader who never opens the SM should still grasp the result, the evidence for it, and why it matters.

• The central claim, its key evidence, and the decisive control live in the Letter.
• The SM holds the exhaustive backup that a skeptical referee or replicator wants.
• Every SM section is cited from the body at the point it is relevant.

If removing the SM breaks the argument, the partition is wrong — pull the essential piece back into the Letter (and trim elsewhere via prl-length-management).

What belongs in Supplemental Material

SM organization

• Mirror the Letter's logic: order SM sections to match the order they are cited.
• Give SM sections their own clear headings (S1, S2, ...) and self-contained captions.
• SM references: include the works the SM itself needs; follow current APS practice on how SM citations are counted and listed (verify).
• Label SM figures/tables distinctly (Fig. S1, Table S1) to avoid confusion with the Letter.
• Keep the SM honest: it is peer-reviewed alongside the Letter, not a place to hide weak results.

Checklist

• The Letter is understandable without ever opening the SM
• No central-claim evidence is only in the SM
• Every SM section is cited from the body at the relevant point
• SM sections ordered to match their citation order in the Letter
• SM figures/tables labeled S1, S2, ... distinctly
• Derivations, extended data, secondary controls live in SM
• SM is internally consistent in notation with the Letter
• SM citation handling follows current APS practice

Anti-patterns

• A Letter that silently depends on the SM to be understood
• Burying the decisive control or key uncertainty in the SM
• An SM that is a disorganized dump rather than a structured appendix
• SM figures referenced out of order or never cited from the body
• Notation drift between Letter and SM
• Using the SM to smuggle in claims the referees did not vet

Output format

【Letter stands alone】yes / fix (pull back: ...)
【SM sections】S1: ... / S2: ... (cited from body?)
【Central evidence only in SM?】none / move back: ...
【SM figure/table labels】S-prefixed?  yes / fix
【Notation consistent Letter↔SM】yes / fix
【Next】prl-writing-style or prl-length-management

SM scope, citation counting, and file-format rules evolve — verify on the official APS / PRL author page.