# Zero resistance: transport evidence and its limits

What a zero-resistance measurement establishes, which controls it needs, and why transport alone does not establish bulk superconductivity.

## Scope

A reported zero resistance means that a specified measurement cannot resolve a resistive voltage under its current, geometry and acquisition conditions. It is evidence within a detection limit, not a measurement of a mathematically exact zero. Keep the measured signal, correction and uncertainty together; a display reading of zero does not specify all three. The uncertainty framework below is separate from a microscopic theory of superconductivity. [R6](#ref-source-0c63f38b6789c792)

Record transition onset, midpoint and the operational zero criterion separately. A conducting path need not occupy the whole specimen. As a simple counterexample, two ideal parallel channels have $R_{\mathrm{eff}}=R_1R_2/(R_1+R_2)$: one zero-resistance channel shorts a finite-resistance channel. This circuit result establishes no volume fraction or material identity. Magnetic and thermodynamic probes answer complementary questions.

## Mathematical assumptions

Suppose a corrected voltage estimate is $\hat V$ and the applied current estimate is $\hat I$. If independently justified intervals satisfy $|V-\hat V|\le U_V$ and $|I-\hat I|\le U_I<|\hat I|$, the triangle inequality gives a conditional bound:

$$\left|\frac{V}{I}\right|\le\frac{|\hat V|+U_V}{|\hat I|-U_I}.$$

This is a local interval calculation, not an automatically calibrated confidence statement. If the input intervals have probabilistic coverage, the output statement must retain that coverage model and their dependence. An operational threshold $|\hat V|<V_{\mathrm{cut}}$ alone does not establish $|V|<V_{\mathrm{cut}}$. Do not substitute a display digit or a noise standard deviation for a validated bound without explaining the choice. NIST's uncertainty guidance distinguishes uncertainty components, applied corrections and coverage. [R6](#ref-source-0c63f38b6789c792)

For a fixed linear resistance and equal opposite currents, model the readings as $V_+=IR+V_{0,+}+\epsilon_+$ and $V_-=-IR+V_{0,-}+\epsilon_-$. Then

$$\hat R=\frac{V_+-V_-}{2I}=R+\frac{V_{0,+}-V_{0,-}+\epsilon_+-\epsilon_-}{2I}.$$

A constant current-even offset cancels. Drift, a current-odd voltage, unequal currents or a changing specimen do not satisfy that cancellation. NIST's shunt report describes a thermoelectric contribution that reverses with the current and therefore survives ordinary reversal averaging. Its apparatus-specific thermal treatment is not a universal correction for superconducting samples. [R5](#ref-source-c8143afdf96ce96f)

With fixed known $I$, the voltage contribution to standard uncertainty is $u_R^2=[u_+^2+u_-^2-2\operatorname{cov}(V_+,V_-)]/(4I^2)$. Current uncertainty and model/systematic contributions must be included separately when present. Independent algebra and finite-outcome checks verify this conditional variance and show why assuming uncorrelated errors can fail. The check is not an instrument calibration. [R6](#ref-source-0c63f38b6789c792)

Converting resistance to resistivity as $\rho=RA/L$ additionally assumes the appropriate homogeneous current path, area $A$ and voltage-contact separation $L$. Four-terminal geometry does not by itself establish uniform current density. Conversely, a passive lumped loop with constant inductance $L_{\mathrm{loop}}$ and resistance obeys $I(t)=I_0e^{-Rt/L_{\mathrm{loop}}}$. For $L_{\mathrm{loop}}\gt0$, elapsed time $t\gt0$ and $0\le\varepsilon<1$, a measured fractional decay of the current magnitude no larger than $\varepsilon$ gives $R\le-L_{\mathrm{loop}}\ln(1-\varepsilon)/t$ only under that loop model. Vortex relaxation or changing inductance needs a different treatment.

## Experimental criteria

Halperin and Nelson's 1979 superconducting-film theory describes a vortex-unbinding regime, fluctuation conductivity and nonlinear resistivity. This supports a limited theoretical reference for thin-film analysis, not a universal fit or a pairing-symmetry test. The publisher abstract was checked; its full derivation has not yet been reviewed here. [R2](#ref-source-9e55a4505d9de546)

Use four-terminal measurements where the time scale and apparatus permit them, and state the actual geometry when they do not. Publish the voltage/current data, detection criterion, field orientation, temperature sweep, bandwidth or integration time and contact configuration. Check current dependence, contact stability and thermal response. Treat these as editorial evidence requirements rather than a claim that one fixed protocol fits every apparatus.

If contacts or backgrounds are subtracted, preserve the original reading and propagate the uncertainty of the subtraction. An independent magnetic or heat-capacity result on a comparable sample helps test a bulk interpretation. A low transport reading alone cannot exclude a connected minority phase, a short or an instrument limitation.

## Limits and disputes

Mitrano and colleagues' earlier author manuscript reports transient optical signatures in driven K3C60 and discusses a high-mobility alternative interpretation. Such spectra do not constitute a direct DC transport measurement. This check covers selected 2015 manuscript passages; the publisher’s 24 February 2016 correction notice identifies a truncated final sentence in the advance-online PDF Figure 4 caption, which was restored. This notice does not replace a full comparison of manuscript and journal versions. No optical crossover temperature is entered as an equilibrium transition. [R3](#ref-source-6ee3670220e24ff1)

Budden and colleagues complement optics with a 1 ns electrical probe of a driven K3C60 pellet at 100 K. The checked manuscript uses a two-terminal transient measurement with contact resistance calibrated against static four-terminal measurements. Figure 4 explicitly includes a calibration-related systematic uncertainty. A resistance compatible with zero in this driven experiment is not an equilibrium $T_{c,\mathrm{zero}}$. The numerical waveform and complete final journal version were not independently reanalyzed. [R4](#ref-source-07be806c0002c690)

These methods probe different observables and time windows. Keep optical extrapolation to zero frequency separate from electrical response, and distinguish either from long-time equilibrium transport. A very large photoconductivity can motivate further tests without resolving every question about phase coherence or magnetic expulsion.

## Discovery implications

A useful discovery report states which observations would distinguish a superconducting path from a contact artifact, minority phase or alternative conducting state. Repeat under controlled current and magnetic field, retain unsuccessful controls, and seek independent probes of the claimed phase. Field suppression supports an interpretation but does not uniquely identify a pairing interaction.

BCS theory is retained as a microscopic background reference, with its detailed treatment in the linked BCS entry. It is not the source for the measurement bounds or procedural requirements developed here. Keep operational transport evidence, theoretical interpretation and claims of bulk superconductivity distinct. [R1](#ref-source-ba10e800a1246bf6)

## Related topics

Read [Meissner evidence](/scwiki/meissner-effect), [specific heat](/scwiki/specific-heat-jump), [critical current](/scwiki/critical-current), [BCS theory](/scwiki/bcs-weak-coupling), [two-dimensional superconductivity](/scwiki/two-dimensional-interfaces), and [Planckian dissipation](/scwiki/planckian-dissipation).

## Material cases

Values describe individual reports, not a ranking. Unknown means the checked source did not supply the field at this review scope.

| Material and sample | Reported temperature | Criterion | Probe | Pressure | State | Evidence |
|---|---|---|---|---|---|---|
| K3C60 (aliases: fulleride, fullerides); optically driven fulleride | no equilibrium Tc assigned | transient-response; transient-optical-response | time-resolved optical conductivity | unknown; unknown GPa | transient | experiment; [source](#ref-source-6ee3670220e24ff1) |
| K3C60 (aliases: fulleride, fullerides); driven pellet in Budden et al. earlier manuscript v1, Fig. 4 and supplement S7 | 100 K; base temperature during driven measurement, not equilibrium Tc | transient-response; transient-two-terminal-response | 1 ns electrical probe; contact calibration from static four-terminal measurement; systematic calibration uncertainty retained | unknown; unknown GPa | transient | experiment; [source](#ref-source-07be806c0002c690) |

## Sources

### Ref source-ba10e800a1246bf6

[R1] Theory of Superconductivity (1957). [DOI 10.1103/PhysRev.108.1175](https://doi.org/10.1103/PhysRev.108.1175). Publication: journal-article. Check: crossref-metadata-only. Checked: 2026-10-17. Bibliographic identity only in A1. Retained as microscopic background; operational bounds and measurement guidance are separate. Selected BCS primary passages checked in B1 must not silently upgrade A1 claims.
### Ref source-9e55a4505d9de546

[R2] Resistive transition in superconducting films (1979). [DOI 10.1007/BF00116988](https://doi.org/10.1007/BF00116988). Publication: journal-article. Check: primary-abstract-scoped-check. Checked: 2026-10-18. Publisher abstract only: dirty superconducting-film vortex-unbinding treatment, fluctuation conductivity and nonlinear resistivity. Full text is subscription-restricted; derivation, numerical applications and other A1 claims are not verified by this check.
### Ref source-6ee3670220e24ff1

[R3] Possible light-induced superconductivity in K3C60 at high temperature (2016). [DOI 10.1038/nature16522](https://doi.org/10.1038/nature16522). Publication: journal-article. Check: earlier-author-manuscript-scoped-check. Checked: 2026-10-19. Selected pp. 1–2 and 4–6 of 2015 v1: transient optical response, high-mobility alternative and finite probe window. Earlier version with different title. The publisher’s 24 February 2016 notice identifies a restored, previously truncated final sentence in the advance-online PDF Figure 4 caption. No full version comparison, raw-data reproduction or equilibrium Tc extraction.
### Ref source-07be806c0002c690

[R4] Evidence for metastable photo-induced superconductivity in K3C60 (2021). [DOI 10.1038/s41567-020-01148-1](https://doi.org/10.1038/s41567-020-01148-1). Publication: journal-article. Check: author-manuscript-scoped-check. Checked: 2026-10-18. Selected p. 9/Fig. 4 and supplement S7 pp. 29–31: 1 ns two-terminal probe, static four-terminal contact calibration, 100 K driven sample and calibration uncertainty. Earlier v1 Feb 2020 linked to 2021 journal article; final methods and data not exhaustively compared.
### Ref source-c8143afdf96ce96f

[R5] A Four-Terminal Current Shunt with Calculable AC Response (2004). [DOI 10.6028/NIST.TN.1462](https://doi.org/10.6028/NIST.TN.1462). Publication: technical-report. Check: primary-report-scoped-check. Checked: 2026-10-18. Selected section 2.5, printed p. 11, and section 5.7, p. 28: thermoelectric effects can reverse with current and survive averaging; constant offsets treated separately. Calibration-shunt methodology, not a superconducting-material study.
### Ref source-0c63f38b6789c792

[R6] Guidelines for Evaluating and Expressing the Uncertainty of NIST Measurement Results, 1994 Edition (1994). [DOI 10.6028/NIST.TN.1297](https://doi.org/10.6028/NIST.TN.1297). Publication: technical-report. Check: primary-report-scoped-check. Checked: 2026-10-18. Selected sections 5–6 and Appendix A: uncertainty propagation including covariance, systematic corrections and coverage factors. Local interval/circuit examples are independent deductions, not an instrument-specific calibration.

## Claim evidence and conditions

### scwiki-a1-claim-scope-1

A reported zero resistance means that a specified measurement cannot resolve a resistive voltage under its current, geometry and acquisition conditions. It is evidence within a detection limit, not a measurement of a mathematically exact zero. Keep the measured signal, correction and uncertainty together; a display reading of zero does not specify all three. The uncertainty framework below is separate from a microscopic theory of superconductivity.

Evidence: hypothesis. Sources: source-0c63f38b6789c792.

Conditions: Editorial measurement/inference guidance; actual specimen, contacts, time window, uncertainty and controls required. No newly acquired experimental data.

Verification scope: Pinned chapter edited with specific methodological references; no broad attribution of procedures to BCS theory.

### scwiki-a1-claim-scope-2

Record transition onset, midpoint and the operational zero criterion separately. A conducting path need not occupy the whole specimen. As a simple counterexample, two ideal parallel channels have $R_{\mathrm{eff}}=R_1R_2/(R_1+R_2)$: one zero-resistance channel shorts a finite-resistance channel. This circuit result establishes no volume fraction or material identity. Magnetic and thermodynamic probes answer complementary questions.

Evidence: theory. Sources: source-0c63f38b6789c792.

Conditions: Conditional interval bounds require valid voltage/current intervals and nonzero lower current magnitude. Reversal assumes equal opposite currents and unchanged linear R; covariance expression fixes I. Circuit and constant-L passive loop examples are ideal models.

Verification scope: Independent algebra, interval-corner, finite-outcome covariance and circuit checks; NIST methodological passages support uncertainty/offset limits, not specimen validation.

### scwiki-a1-claim-mathematical-assumptions-1

Suppose a corrected voltage estimate is $\hat V$ and the applied current estimate is $\hat I$. If independently justified intervals satisfy $|V-\hat V|\le U_V$ and $|I-\hat I|\le U_I<|\hat I|$, the triangle inequality gives a conditional bound:

Evidence: theory. Sources: source-0c63f38b6789c792.

Source relationship: context-for-local-derivation. Conditional interval inequality derived locally; linked NIST guidance supplies uncertainty and coverage methodology, not this exact resistance bound.

Conditions: Conditional interval bounds require valid voltage/current intervals and nonzero lower current magnitude. Reversal assumes equal opposite currents and unchanged linear R; covariance expression fixes I. Circuit and constant-L passive loop examples are ideal models.

Verification scope: Independent algebra, interval-corner, finite-outcome covariance and circuit checks; NIST methodological passages support uncertainty/offset limits, not specimen validation.

### scwiki-a1-claim-mathematical-assumptions-2

$$\left|\frac{V}{I}\right|\le\frac{|\hat V|+U_V}{|\hat I|-U_I}.$$

Evidence: theory. Sources: source-0c63f38b6789c792.

Conditions: Conditional interval bounds require valid voltage/current intervals and nonzero lower current magnitude. Reversal assumes equal opposite currents and unchanged linear R; covariance expression fixes I. Circuit and constant-L passive loop examples are ideal models.

Verification scope: Independent algebra, interval-corner, finite-outcome covariance and circuit checks; NIST methodological passages support uncertainty/offset limits, not specimen validation.

### scwiki-a1-claim-mathematical-assumptions-3

This is a local interval calculation, not an automatically calibrated confidence statement. If the input intervals have probabilistic coverage, the output statement must retain that coverage model and their dependence. An operational threshold $|\hat V|<V_{\mathrm{cut}}$ alone does not establish $|V|<V_{\mathrm{cut}}$. Do not substitute a display digit or a noise standard deviation for a validated bound without explaining the choice. NIST's uncertainty guidance distinguishes uncertainty components, applied corrections and coverage.

Evidence: theory. Sources: source-0c63f38b6789c792.

Conditions: Conditional interval bounds require valid voltage/current intervals and nonzero lower current magnitude. Reversal assumes equal opposite currents and unchanged linear R; covariance expression fixes I. Circuit and constant-L passive loop examples are ideal models.

Verification scope: Independent algebra, interval-corner, finite-outcome covariance and circuit checks; NIST methodological passages support uncertainty/offset limits, not specimen validation.

### scwiki-a1-claim-mathematical-assumptions-4

For a fixed linear resistance and equal opposite currents, model the readings as $V_+=IR+V_{0,+}+\epsilon_+$ and $V_-=-IR+V_{0,-}+\epsilon_-$. Then

Evidence: theory. Sources: source-0c63f38b6789c792.

Conditions: Conditional interval bounds require valid voltage/current intervals and nonzero lower current magnitude. Reversal assumes equal opposite currents and unchanged linear R; covariance expression fixes I. Circuit and constant-L passive loop examples are ideal models.

Verification scope: Independent algebra, interval-corner, finite-outcome covariance and circuit checks; NIST methodological passages support uncertainty/offset limits, not specimen validation.

### scwiki-a1-claim-mathematical-assumptions-5

$$\hat R=\frac{V_+-V_-}{2I}=R+\frac{V_{0,+}-V_{0,-}+\epsilon_+-\epsilon_-}{2I}.$$

Evidence: theory. Sources: source-0c63f38b6789c792.

Source relationship: context-for-local-derivation. Algebraic subtraction of the two stated voltage models; linked references are measurement context, not direct verification of this formula.

Conditions: Conditional interval bounds require valid voltage/current intervals and nonzero lower current magnitude. Reversal assumes equal opposite currents and unchanged linear R; covariance expression fixes I. Circuit and constant-L passive loop examples are ideal models.

Verification scope: Independent algebra, interval-corner, finite-outcome covariance and circuit checks; NIST methodological passages support uncertainty/offset limits, not specimen validation.

### scwiki-a1-claim-mathematical-assumptions-6

A constant current-even offset cancels. Drift, a current-odd voltage, unequal currents or a changing specimen do not satisfy that cancellation. NIST's shunt report describes a thermoelectric contribution that reverses with the current and therefore survives ordinary reversal averaging. Its apparatus-specific thermal treatment is not a universal correction for superconducting samples.

Evidence: theory. Sources: source-c8143afdf96ce96f.

Conditions: Conditional interval bounds require valid voltage/current intervals and nonzero lower current magnitude. Reversal assumes equal opposite currents and unchanged linear R; covariance expression fixes I. Circuit and constant-L passive loop examples are ideal models.

Verification scope: Independent algebra, interval-corner, finite-outcome covariance and circuit checks; NIST methodological passages support uncertainty/offset limits, not specimen validation.

### scwiki-a1-claim-mathematical-assumptions-7

With fixed known $I$, the voltage contribution to standard uncertainty is $u_R^2=[u_+^2+u_-^2-2\operatorname{cov}(V_+,V_-)]/(4I^2)$. Current uncertainty and model/systematic contributions must be included separately when present. Independent algebra and finite-outcome checks verify this conditional variance and show why assuming uncorrelated errors can fail. The check is not an instrument calibration.

Evidence: theory. Sources: source-0c63f38b6789c792.

Conditions: Conditional interval bounds require valid voltage/current intervals and nonzero lower current magnitude. Reversal assumes equal opposite currents and unchanged linear R; covariance expression fixes I. Circuit and constant-L passive loop examples are ideal models.

Verification scope: Independent algebra, interval-corner, finite-outcome covariance and circuit checks; NIST methodological passages support uncertainty/offset limits, not specimen validation.

### scwiki-a1-claim-mathematical-assumptions-8

Converting resistance to resistivity as $\rho=RA/L$ additionally assumes the appropriate homogeneous current path, area $A$ and voltage-contact separation $L$. Four-terminal geometry does not by itself establish uniform current density. Conversely, a passive lumped loop with constant inductance $L_{\mathrm{loop}}$ and resistance obeys $I(t)=I_0e^{-Rt/L_{\mathrm{loop}}}$. For $L_{\mathrm{loop}}\gt0$, elapsed time $t\gt0$ and $0\le\varepsilon<1$, a measured fractional decay of the current magnitude no larger than $\varepsilon$ gives $R\le-L_{\mathrm{loop}}\ln(1-\varepsilon)/t$ only under that loop model. Vortex relaxation or changing inductance needs a different treatment.

Evidence: theory. Sources: source-0c63f38b6789c792.

Source relationship: context-for-local-derivation. Local homogeneous-path and constant passive RL-loop deductions; L_loop>0, t>0 and 0<=epsilon<1 are required. Contextual references do not certify a measured persistent current.

Conditions: Conditional interval bounds require valid voltage/current intervals and nonzero lower current magnitude. Reversal assumes equal opposite currents and unchanged linear R; covariance expression fixes I. Circuit and constant-L passive loop examples are ideal models. Constant passive R>=0, L_loop>0, elapsed t>0, and 0<=epsilon<1 for the current-magnitude decay bound.

Verification scope: Independent algebra, interval-corner, finite-outcome covariance and circuit checks; NIST methodological passages support uncertainty/offset limits, not specimen validation.

### scwiki-a1-claim-experimental-criteria-1

Halperin and Nelson's 1979 superconducting-film theory describes a vortex-unbinding regime, fluctuation conductivity and nonlinear resistivity. This supports a limited theoretical reference for thin-film analysis, not a universal fit or a pairing-symmetry test. The publisher abstract was checked; its full derivation has not yet been reviewed here.

Evidence: theory. Sources: source-9e55a4505d9de546.

Conditions: Dirty superconducting-film vortex-unbinding regime; fit assumptions and sample conditions must be checked independently.

Verification scope: Publisher abstract only; full derivation not accessed.

### scwiki-a1-claim-experimental-criteria-2

Use four-terminal measurements where the time scale and apparatus permit them, and state the actual geometry when they do not. Publish the voltage/current data, detection criterion, field orientation, temperature sweep, bandwidth or integration time and contact configuration. Check current dependence, contact stability and thermal response. Treat these as editorial evidence requirements rather than a claim that one fixed protocol fits every apparatus.

Evidence: hypothesis. Sources: source-0c63f38b6789c792.

Conditions: Editorial measurement/inference guidance; actual specimen, contacts, time window, uncertainty and controls required. No newly acquired experimental data.

Verification scope: Pinned chapter edited with specific methodological references; no broad attribution of procedures to BCS theory.

### scwiki-a1-claim-experimental-criteria-3

If contacts or backgrounds are subtracted, preserve the original reading and propagate the uncertainty of the subtraction. An independent magnetic or heat-capacity result on a comparable sample helps test a bulk interpretation. A low transport reading alone cannot exclude a connected minority phase, a short or an instrument limitation.

Evidence: hypothesis. Sources: source-0c63f38b6789c792.

Conditions: Editorial measurement/inference guidance; actual specimen, contacts, time window, uncertainty and controls required. No newly acquired experimental data.

Verification scope: Pinned chapter edited with specific methodological references; no broad attribution of procedures to BCS theory.

### scwiki-a1-claim-limits-and-disputes-1

Mitrano and colleagues' earlier author manuscript reports transient optical signatures in driven K3C60 and discusses a high-mobility alternative interpretation. Such spectra do not constitute a direct DC transport measurement. This check covers selected 2015 manuscript passages; the publisher’s 24 February 2016 correction notice identifies a truncated final sentence in the advance-online PDF Figure 4 caption, which was restored. This notice does not replace a full comparison of manuscript and journal versions. No optical crossover temperature is entered as an equilibrium transition.

Evidence: experiment. Sources: source-6ee3670220e24ff1.

Conditions: Driven K3C60, explicitly limited manuscript version. Optical signatures are distinct from the 100 K two-terminal transient electrical measurement with static four-terminal calibration; neither defines equilibrium Tc.

Verification scope: Selected Mitrano v1 pp. 1–2/4–6 or Budden v1 p. 9 and supplement S7 pp. 29–31; full final data/version comparison remains open.

### scwiki-a1-claim-limits-and-disputes-2

Budden and colleagues complement optics with a 1 ns electrical probe of a driven K3C60 pellet at 100 K. The checked manuscript uses a two-terminal transient measurement with contact resistance calibrated against static four-terminal measurements. Figure 4 explicitly includes a calibration-related systematic uncertainty. A resistance compatible with zero in this driven experiment is not an equilibrium $T_{c,\mathrm{zero}}$. The numerical waveform and complete final journal version were not independently reanalyzed.

Evidence: experiment. Sources: source-07be806c0002c690.

Conditions: Driven K3C60, explicitly limited manuscript version. Optical signatures are distinct from the 100 K two-terminal transient electrical measurement with static four-terminal calibration; neither defines equilibrium Tc.

Verification scope: Selected Mitrano v1 pp. 1–2/4–6 or Budden v1 p. 9 and supplement S7 pp. 29–31; full final data/version comparison remains open.

### scwiki-a1-claim-limits-and-disputes-3

These methods probe different observables and time windows. Keep optical extrapolation to zero frequency separate from electrical response, and distinguish either from long-time equilibrium transport. A very large photoconductivity can motivate further tests without resolving every question about phase coherence or magnetic expulsion.

Evidence: hypothesis. Sources: source-0c63f38b6789c792.

Conditions: Editorial measurement/inference guidance; actual specimen, contacts, time window, uncertainty and controls required. No newly acquired experimental data.

Verification scope: Pinned chapter edited with specific methodological references; no broad attribution of procedures to BCS theory.

### scwiki-a1-claim-discovery-implications-1

A useful discovery report states which observations would distinguish a superconducting path from a contact artifact, minority phase or alternative conducting state. Repeat under controlled current and magnetic field, retain unsuccessful controls, and seek independent probes of the claimed phase. Field suppression supports an interpretation but does not uniquely identify a pairing interaction.

Evidence: hypothesis. Sources: source-0c63f38b6789c792.

Conditions: Editorial measurement/inference guidance; actual specimen, contacts, time window, uncertainty and controls required. No newly acquired experimental data.

Verification scope: Pinned chapter edited with specific methodological references; no broad attribution of procedures to BCS theory.

### scwiki-a1-claim-discovery-implications-2

BCS theory is retained as a microscopic background reference, with its detailed treatment in the linked BCS entry. It is not the source for the measurement bounds or procedural requirements developed here. Keep operational transport evidence, theoretical interpretation and claims of bulk superconductivity distinct.

Evidence: hypothesis. Sources: source-ba10e800a1246bf6.

Conditions: Editorial measurement/inference guidance; actual specimen, contacts, time window, uncertainty and controls required. No newly acquired experimental data.

Verification scope: Pinned chapter edited with specific methodological references; no broad attribution of procedures to BCS theory.

## Revision and review

Article ID: scwiki-a1. Revision: acc864304b601c72931f. Updated: 2026-10-19.

Review scope: Operational transport bounds and model checks; selected NIST metrology report passages, earlier optical/electrical K3C60 manuscript passages and existing Halperin–Nelson abstract check. Publisher notice identifying the 24 February 2016 Mitrano caption correction checked separately on 19 October 2026.

- No full scientific acceptance, experimental replication or instrument calibration is claimed.
- Input uncertainty intervals and response models must be justified for the actual apparatus; mathematical checks do not establish their experimental validity.
- Mitrano’s 24 February 2016 caption-correction notice is identified; earlier manuscripts remain explicit and no exhaustive old/corrected/final-version comparison was performed.
- Driven K3C60 observations are not equilibrium transition-temperature records; BCS remains a background reference in this entry.

Source: [A_phenomenology/A1_zero_resistivity.md](https://github.com/JackZH26/jzis-superconductivity/blob/0a7c9d6696804ec26aa12f8eed68b55c9b3c0fcf/A_phenomenology/A1_zero_resistivity.md), commit 0a7c9d6696804ec26aa12f8eed68b55c9b3c0fcf, SHA-256 8be1b0c5e8c7dcb8c898385914d0a17523befbf3ddc319c6c88950cbaf9fb9ca.