The Double Well Done Doubly-Well
Pith reviewed 2026-06-28 05:06 UTC · model grok-4.3
The pith
Resurgence organizes the exact spectrum of the symmetric double well into a single tightly-constrained trans-series.
A machine-rendered reading of the paper's core claim, the machinery that carries it, and where it could break.
Core claim
The symmetric double well's energy spectrum forms a single resurgence trans-series. In exact WKB the Delabaere-Dillinger-Pham relations encode the Stokes phenomena that control analytic continuation of the wave function past turning points, and the resulting quantization condition in Voros symbols yields the complete trans-series. In the path integral the classical saddles are elliptic functions of Euclidean time, and a Lefschetz thimble decomposition on the quasi-zero-mode manifold selects the contributing saddles, producing a simpler trans-series whose T-dependence at each instanton order is a fixed polynomial.
What carries the argument
The resurgence trans-series for the energy levels, fixed by Delabaere-Dillinger-Pham relations in exact WKB and by Lefschetz thimble integrals over quasi-zero modes in the path integral.
If this is right
- The quantization condition expressed in Voros symbols determines the entire trans-series from the local Stokes data alone.
- At each instanton order the path-integral partition-function trans-series has a polynomial time dependence fixed solely by the thimble integrals.
- The energy trans-series is more intricate than the partition-function trans-series, yet both are consistent through the computed orders.
- The elliptic curve structure of the energy surface appears in both approaches but enters through different mechanisms.
Where Pith is reading between the lines
- The same local Stokes and thimble machinery may organize spectra for other potentials whose classical saddles form elliptic curves.
- Extending the explicit calculations to five or six instantons would provide a direct test of whether the pattern continues without new parameters.
- The wave-function trans-series itself, not only the energies, could be extracted from the same WKB data for comparison with numerical solutions.
Load-bearing premise
The local Delabaere-Dillinger-Pham relations together with the Lefschetz thimble decomposition on the quasi-zero-mode manifold suffice to fix the full trans-series without additional global information or fitting parameters.
What would settle it
An independent high-precision numerical computation of the energy levels that finds coefficients at four-instanton three-loop order differing from the predicted trans-series values would disprove the claimed organization.
Figures
read the original abstract
The symmetric double-well potential is one of the simplest quantum-mechanical systems in which perturbative and non-perturbative physics are deeply entangled. Its energy levels have non-analytic expansions in inverse powers of the inter-well separation, with factorially growing coefficients, while the parity splitting is exponentially small and invisible to perturbation theory. Resurgence ties the two features together, organizing the exact spectrum into a single tightly-constrained trans-series. This paper gives a self-contained account of this trans-series from two complementary approaches: exact WKB and the Euclidean path integral, developed in a common notation with explicit calculations through the four-instanton level and three-loop order. In exact WKB, Stokes phenomena encoded in the Delabaere--Dillinger--Pham relations control the analytic continuation of the wavefunction past turning points. The quantization condition expressed in terms of Voros symbols then determines the full trans-series. The DDP relations are local and do not require knowing the global topology of the energy surface, but that surface is an elliptic curve. In the path integral, elliptic curves enter differently: the classical saddle points are doubly-periodic elliptic functions of Euclidean time, and Stokes phenomena play out within the finite-dimensional manifold of quasi-zero modes rather than through analytic continuation of the wavefunction. A Lefschetz thimble decomposition determines which saddles contribute, and the resulting partition function trans-series is much simpler than the energy trans-series: at each instanton order the $T$-dependence is a polynomial fixed by the quasi-zero-mode thimble integrals. Together, the two approaches deploy a shared mathematical infrastructure in complementary ways, showing that the double well is an ideal setting to explore resurgence.
Editorial analysis
A structured set of objections, weighed in public.
Referee Report
Summary. The paper claims to provide a self-contained derivation of the trans-series for both the energy levels and the partition function of the symmetric double-well potential. It employs exact WKB with Delabaere-Dillinger-Pham (DDP) Stokes relations for the quantization condition in terms of Voros symbols, together with the Euclidean path integral using Lefschetz thimble decomposition over the quasi-zero-mode manifold, yielding explicit results through four-instanton order and three-loop order. The central assertion is that these local relations and thimble integrals determine all trans-series coefficients without global elliptic-curve periods or fitting parameters.
Significance. If the explicit calculations are correct, the work would be significant as a detailed benchmark for resurgence techniques in quantum mechanics, showing how two complementary formalisms (exact WKB and path integrals) produce consistent trans-series in a shared notation. The explicit four-instanton, three-loop results and the demonstration that local DDP relations suffice despite the elliptic-curve energy surface constitute a concrete strength; the paper ships explicit calculations at high perturbative and non-perturbative orders.
minor comments (2)
- The abstract is lengthy and contains several technical clauses; a shorter version focused on the main results and the parameter-free character of the construction would improve accessibility.
- The title is informal; consider whether a more descriptive title would better suit the journal's conventions while retaining the pun if desired.
Simulated Author's Rebuttal
We thank the referee for their positive summary, recognition of the significance of the explicit four-instanton calculations, and recommendation of minor revision. No specific major comments appear in the report.
Circularity Check
Derivation self-contained from exact WKB and path integrals; no reduction to inputs by construction
full rationale
The paper presents explicit four-instanton, three-loop trans-series for the double-well spectrum derived from Delabaere-Dillinger-Pham (DDP) Stokes relations in exact WKB and from Lefschetz thimble integrals over the quasi-zero-mode manifold in the path integral. The abstract and description state that DDP relations are local (do not require global elliptic-curve topology) and that thimble integrals fix the polynomial T-dependence at each order. No equations or claims indicate that coefficients are fitted to data, defined in terms of the output trans-series, or obtained via self-citation load-bearing steps. The construction is presented as parameter-free once the local relations and thimble decomposition are applied, consistent with the reader's assessment of score 2.0. No self-definitional, fitted-input, or ansatz-smuggling patterns appear in the provided text.
Axiom & Free-Parameter Ledger
Reference graph
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