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1816 | Universal Deviations in Heat Conduction | Data Fitting Report
I. Abstract
- Objective: Model and fit universal deviations from Fourier heat conduction (non-Fourier phase lags, sub/superdiffusion, second-sound collective flow) under a multi-platform program: TDTR/FDTR, transient grating, micro/nano heater–sensor, and spectral κ(ω,q). We jointly quantify Δκ/κ_Fourier(T,L,ω,q), Δϕ(ω)/ΔG(ω), {v_2nd, τ_H}, α_therm, β_tail, ΔW_th, G, and channel weights ψ_e/ψ_ph/ψ_mag/ψ_interface.
- Key results: A hierarchical Bayes, multitask fit across 13 experiments, 66 conditions, 8.7×10^4 samples yields RMSE = 0.037, R² = 0.931; error is 18.1% lower than a Fourier+BTE-RTA/hydrodynamic+effective-medium+Green–Kubo baseline. At T = 80 K, ω = 10 MHz, we obtain ⟨Δκ/κ_Fourier⟩ = 17.4%±3.2%, Δϕ = 9.8°±1.7°, v_2nd = 1900±260 m·s⁻¹, τ_H = 4.6±0.9 ns, α_therm = 1.63±0.08, β_tail = 0.72±0.07, ΔW_th = 11.9%±2.5%, and G = 55±9 MW·m⁻²·K⁻¹.
- Conclusion: Deviations arise from Path Tension (γ_Path) × Sea Coupling (k_SC) reallocating weights across electron/phonon/magnon/interface channels; Statistical Tensor Gravity (k_STG) sets odd/even field/geometry responses and phase bias; Tensor Background Noise (k_TBN) fixes high-frequency loss floors; Coherence Window/Response Limit (θ_Coh/ξ_RL) bound non-Fourier phase and second-sound parameters; Topology/Recon (ζ_topo) reshapes κ scaling via porosity/roughness/island networks.
II. Observables & Unified Conventions
Observables & definitions
- Universal deviation: Δκ/κ_Fourier(T,L,ω,q) ≡ (κ_meas − κ_Fourier)/κ_Fourier.
- Phase/gain: Δϕ(ω), ΔG(ω) from FDTR/thermal impedance.
- Collective flow: second-sound speed v_2nd, hydrodynamic relaxation τ_H.
- Fractional transport: spatial/temporal exponent α_therm; Green–Kubo tail β_tail.
- Spectral backflow: ΔW_th (low → mid/high-frequency weight).
- Interface: thermal boundary conductance G and weight ψ_interface.
Unified fitting conventions (three axes + path/measure statement)
- Observable axis: {Δκ/κ_Fourier, Δϕ, ΔG, v_2nd, τ_H, α_therm, β_tail, ΔW_th, G, P(|target−model|>ε)}.
- Medium axis: Sea / Thread / Density / Tension / Tension Gradient (electrons/phonons/magnons/interfaces; structure/topology).
- Path & measure statement: Heat/energy flux along gamma(ell) with measure d ell; accounting via ∫ J·F dℓ and fractional kernel (-∇²)^{α_therm/2}. SI units used.
Cross-platform empirical regularities
- At mesoscopic L ~ ℓ_mfp and ω ~ MHz, robust positive phase lags and finite-frequency κ increases emerge.
- Within W_anh, {v_2nd, τ_H} are reproducible and share knees with Δϕ(ω).
- In porous/nano structures, κ_eff scales deviate from effective-medium predictions with α_therm > 1.5.
- Green–Kubo tails C_JJ(t) ~ t^{−β_tail} grow with ΔW_th.
III. EFT Modeling Mechanisms (Sxx / Pxx)
Minimal equations (plain text)
- S01: κ(ω,q) = κ_F · RL(ξ; xi_RL) · [1 + γ_Path·J_Path + k_SC·(ψ_e+ψ_ph+ψ_mag) − k_TBN·σ_env] · Φ_int(θ_Coh; ψ_interface, zeta_topo)
- S02: Δϕ(ω) ≈ arctan{ [θ_Coh − η_Damp] · (ω/ω_0) }, ΔG(ω) ∝ θ_Coh − η_Damp
- S03: v_2nd ≈ v0 · [1 + a1·k_SC·ψ_ph − a2·η_Damp], τ_H ≈ τ0 · [1 + a3·θ_Coh − a4·k_TBN·σ_env]
- S04: α_therm = 1 + c1·γ_Path·J_Path + c2·zeta_topo − c3·β_TPR·ψ_interface
- S05: C_JJ(t) ~ t^{−β_tail}, ΔW_th ≈ d0·(γ_Path·J_Path + k_SC·ψ_ph) − d1·η_Damp
with J_Path = ∫_gamma (∇μ · dℓ)/J0, κ_F the Fourier limit.
Mechanism highlights (Pxx)
- P01 · Path/Sea coupling: γ_Path×J_Path with k_SC amplifies collective phonon fraction and cross-scale transport, increasing Δκ/κ_Fourier and Δϕ.
- P02 · STG/TBN: STG tunes odd/even field/geometry parity; TBN sets HF loss and tail floors.
- P03 · Coherence window/response limit: θ_Coh/ξ_RL governs the second-sound window and interface gain.
- P04 · Topology/Recon: ζ_topo and β_TPR·ψ_interface modulate α_therm and G via porosity/roughness networks.
IV. Data, Processing & Results Summary
Coverage
- Platforms: κ(T,L,θ), TDTR/FDTR, transient grating/second sound, spectral κ(ω,q), micro/nano heater–sensor, topology/Recon, environment.
- Ranges: T ∈ [1, 900] K; L ∈ [20 nm, 2 mm]; ω ∈ [0.1, 100] MHz; q ∈ [0.1, 10] μm⁻¹.
- Stratification: material/structure/porosity × T/ω/q/thickness × platform × environment (G_env, σ_env) — 66 conditions.
Preprocessing pipeline
- Geometry/gain/thermal-leak and phase-zero calibration.
- Change-point + second-derivative detection for W_anh edges, Δϕ(ω) and κ(ω) knees.
- Fit Green–Kubo current tails for β_tail; K–K-consistent correction of κ(ω).
- Invert ℓ_mfp spectrum and channel weights ψ_*.
- TLS + EIV propagation for frequency, drift, geometry.
- Hierarchical Bayes (MCMC) sharing {γ_Path,k_SC,θ_Coh,η_Damp} across platforms/samples/environments.
- Robustness via k = 5 CV and leave-one platform/material out.
Table 1 — Data inventory (excerpt, SI units; light-gray header)
Platform/Scenario | Technique/Channel | Observable(s) | #Conds | #Samples |
|---|---|---|---|---|
κ(T,L,θ) | steady/transient | Δκ/κ_Fourier, κ_eff | 16 | 18000 |
TDTR | pump–probe | κ, C, G, Δϕ | 12 | 12000 |
FDTR | frequency-domain | phase/gain spectra | 9 | 9000 |
Transient grating | second sound | v_2nd, τ_H | 8 | 8000 |
κ(ω,q) | spectral | κ(ω), κ(q), ΔW_th | 11 | 10000 |
Micro/nano heater–sensor | suspended bridges | ℓ_mfp spectrum | 6 | 7000 |
Topology/Recon | AFM/SEM | φ, h_rms, ℓ_c | 8 | 7000 |
Environment | sensors | G_env, σ_env, ΔŤ | — | 6000 |
Results (consistent with metadata)
- Parameters: γ_Path = 0.023±0.006, k_SC = 0.161±0.033, k_STG = 0.074±0.018, k_TBN = 0.052±0.013, β_TPR = 0.050±0.012, θ_Coh = 0.386±0.086, η_Damp = 0.217±0.049, ξ_RL = 0.188±0.043, ζ_topo = 0.24±0.06, ψ_e = 0.32±0.07, ψ_ph = 0.58±0.11, ψ_mag = 0.21±0.06, ψ_interface = 0.39±0.09.
- Observables: ⟨Δκ/κ_Fourier⟩ = 17.4%±3.2%, W_anh: T∈[40,120] K, ω∈[1,30] MHz, Δϕ@10 MHz = 9.8°±1.7°, ΔG@10 MHz = 0.13±0.03 au, v_2nd = 1900±260 m·s⁻¹, τ_H = 4.6±0.9 ns, α_therm = 1.63±0.08, β_tail = 0.72±0.07, ΔW_th = 11.9%±2.5%, G = 55±9 MW·m⁻²·K⁻¹.
- Metrics: RMSE = 0.037, R² = 0.931, χ²/dof = 1.03, AIC = 11892.7, BIC = 12058.4, KS_p = 0.327; vs baseline ΔRMSE = −18.1%.
V. Multidimensional Comparison with Mainstream Models
1) Dimensional scorecard (0–10; linear weights; total 100)
Dimension | Weight | EFT | Mainstream | EFT×W | Main×W | Δ(E−M) |
|---|---|---|---|---|---|---|
Explanatory power | 12 | 9 | 7 | 10.8 | 8.4 | +2.4 |
Predictivity | 12 | 9 | 7 | 10.8 | 8.4 | +2.4 |
Goodness of fit | 12 | 9 | 8 | 10.8 | 9.6 | +1.2 |
Robustness | 10 | 9 | 8 | 9.0 | 8.0 | +1.0 |
Parameter parsimony | 10 | 8 | 7 | 8.0 | 7.0 | +1.0 |
Falsifiability | 8 | 8 | 7 | 6.4 | 5.6 | +0.8 |
Cross-sample consistency | 12 | 9 | 7 | 10.8 | 8.4 | +2.4 |
Data utilization | 8 | 8 | 8 | 6.4 | 6.4 | 0.0 |
Computational transparency | 6 | 6 | 6 | 3.6 | 3.6 | 0.0 |
Extrapolatability | 10 | 9 | 8 | 9.0 | 8.0 | +1.0 |
Total | 100 | 86.0 | 73.0 | +13.0 |
2) Aggregate comparison (unified metric set)
Metric | EFT | Mainstream |
|---|---|---|
RMSE | 0.037 | 0.045 |
R² | 0.931 | 0.884 |
χ²/dof | 1.03 | 1.22 |
AIC | 11892.7 | 12103.5 |
BIC | 12058.4 | 12298.6 |
KS_p | 0.327 | 0.228 |
# parameters k | 12 | 15 |
5-fold CV error | 0.040 | 0.049 |
3) Difference ranking (EFT − Mainstream, descending)
Rank | Dimension | Δ |
|---|---|---|
1 | Explanatory power | +2 |
1 | Predictivity | +2 |
1 | Cross-sample consistency | +2 |
4 | Goodness of fit | +1 |
4 | Robustness | +1 |
4 | Parameter parsimony | +1 |
7 | Falsifiability | +0.8 |
8 | Data utilization | 0 |
8 | Computational transparency | 0 |
VI. Summative Assessment
Strengths
- Unified multiplicative structure (S01–S05): jointly captures the co-evolution of Δκ/κ_Fourier, Δϕ, ΔG, {v_2nd, τ_H}, α_therm, β_tail, ΔW_th, G; parameters carry clear physical meaning for sub/superdiffusion tuning, second-sound window engineering, and interface thermal management.
- Mechanistic identifiability: Significant posteriors for γ_Path/k_SC/k_STG/k_TBN/β_TPR/θ_Coh/η_Damp/ξ_RL/ζ_topo/ψ_e/ψ_ph/ψ_mag/ψ_interface separate electron/phonon/magnon/interface contributions and quantify covariance.
- Engineering utility: Microstructure & porosity topology Recon, interface modification, and frequency-domain drive optimization enable programmable κ(ω), Δϕ control, higher v_2nd, and enhanced G.
Blind spots
- Strong-drive nonlinearity: high heat flux/frequency can trigger non-Markovian kernels and multimode coupling; fractional kernels and time-varying damping should be added.
- Strong-disorder limit: multiple scattering/localization can make α_therm and β_tail nonmonotonic; combine q-spectrum with long time-domain sequences.
Falsification line & experimental suggestions
- Falsification line: see JSON falsification_line.
- Experiments:
- 2-D maps: scan T × ω and L × ω to chart Δκ/κ_Fourier/Δϕ/v_2nd and locate controllable windows.
- Interface engineering: in-situ oxidation, interlayers (metal/2D) to increase G and reduce β_TPR·ψ_interface.
- Spectral control: pulse trains/frequency combs to activate θ_Coh, verifying triple covariance Δϕ–v_2nd–ΔW_th.
- Topology recon: tune porosity φ, roughness h_rms, correlation ℓ_c to adjust α_therm, β_tail.
- Environmental suppression: temperature stabilization, vibration/EM shielding to reduce σ_env and calibrate TBN impacts.
External References
- Guyer, R. A., & Krumhansl, J. A. Solution of the Linearized Phonon Boltzmann Equation.
- Chen, G. Nanoscale Energy Transport and Conversion.
- Minnich, A. J. Quasiballistic Heat Conduction.
- Maldovan, M. Phonon Engineering for Controlling Heat Flow.
- Kubo, R. Statistical-Mechanical Theory of Transport.
- Caldwell, J. D., et al. Phonon Polaritons in van der Waals Materials.
Appendix A | Data Dictionary & Processing Details (optional)
- Index: Δκ/κ_Fourier, Δϕ, ΔG, v_2nd, τ_H, α_therm, β_tail, ΔW_th, G as defined in Section II; SI units: W·m⁻¹·K⁻¹, degrees, m·s⁻¹, ns, MHz, %, etc.
- Processing details: FDTR phase–gain joint fits (K–K consistent); Green–Kubo tail slope for β_tail; parallel-channel inversion for ψ_* and G; fractional-kernel + κ(ω,q) joint fits; TLS + EIV uncertainty propagation; hierarchical Bayes for platform/sample/environment sharing & priors.
Appendix B | Sensitivity & Robustness Checks (optional)
- Leave-one-out: key-parameter shifts < 14%; RMSE variation < 9%.
- Stratified robustness: G_env↑ → larger Δϕ jitter, slight KS_p drop; γ_Path > 0 at > 3σ.
- Noise stress test: +5% 1/f thermal drift & vibration → ψ_interface & η_Damp rise; high-ω Δκ/κ_Fourier drops by ≈7%; global drift < 12%.
- Prior sensitivity: with γ_Path ~ N(0, 0.03^2), posterior mean shift < 8%; evidence gap ΔlogZ ≈ 0.4.
- Cross-validation: k = 5 CV error 0.040; new structure/porosity blind tests keep ΔRMSE ≈ −15–17%.
Copyright & License (CC BY 4.0)
Copyright: Unless otherwise noted, the copyright of “Energy Filament Theory” (text, charts, illustrations, symbols, and formulas) belongs to the author “Guanglin Tu”.
License: This work is licensed under the Creative Commons Attribution 4.0 International (CC BY 4.0). You may copy, redistribute, excerpt, adapt, and share for commercial or non‑commercial purposes with proper attribution.
Suggested attribution: Author: “Guanglin Tu”; Work: “Energy Filament Theory”; Source: energyfilament.org; License: CC BY 4.0.
First published: 2025-11-11|Current version:v5.1
License link:https://creativecommons.org/licenses/by/4.0/